U.S. patent number 8,598,354 [Application Number 13/153,350] was granted by the patent office on 2013-12-03 for compounds having antiparasitic or anti-infectious activity.
This patent grant is currently assigned to Medicines for Malaria Venture, University of South Florida. The grantee listed for this patent is Jeremy Burrows, Richard M. Cross, David L. Flanigan, David J. Hinrichs, Jane X. Kelly, Dennis Kyle, Roman Manetsch, Andrii Monastyrskyi, Aaron Nilsen, Michael K. Riscoe, Martin J. Smilkstein, Rolf W. Winter. Invention is credited to Jeremy Burrows, Richard M. Cross, David L. Flanigan, David J. Hinrichs, Jane X. Kelly, Dennis Kyle, Roman Manetsch, Andrii Monastyrskyi, Aaron Nilsen, Michael K. Riscoe, Martin J. Smilkstein, Rolf W. Winter.
United States Patent |
8,598,354 |
Riscoe , et al. |
December 3, 2013 |
Compounds having antiparasitic or anti-infectious activity
Abstract
Compounds of formula I: ##STR00001## or formula II: ##STR00002##
or a pharmaceutically acceptable salt of formula I or formula II,
wherein: R.sup.1 is H, hydroxyl, alkoxy, acyl, alkyl, cycloalkyl,
aryl, or heteroaryl; R.sup.2 is methyl or haloalkyl; R.sup.4 is
hydroxyl, carbonyloxy, or carbonyldioxy; and R.sup.3 is aliphatic,
aryl, aralkyl, or alkylaryl; and R.sup.5, R.sup.6, R.sup.7 and
R.sup.8 are each individually H, halogen, alkoxy, alkyl, haloalkyl,
aryl, nitro, cyano, amino, amido, acyl, carboxyl, substituted
carboxyl, or --SO.sub.2R.sup.10, wherein R.sup.10 is H, alkyl,
amino or haloalkyl; provided that in formula I, R.sup.5 and R.sup.7
are not both H or R.sup.6 is not H or methoxy; and in formula II
that if R.sup.4 is carbonyldioxy then R.sup.7 is not methoxy.
Inventors: |
Riscoe; Michael K. (Tualatin,
OR), Kelly; Jane X. (Lake Oswego, OR), Winter; Rolf
W. (Portland, OR), Hinrichs; David J. (Lake Oswego,
OR), Smilkstein; Martin J. (Portland, OR), Nilsen;
Aaron (Portland, OR), Burrows; Jeremy (Eysins,
CH), Kyle; Dennis (Lithia, FL), Manetsch;
Roman (Tampa, FL), Cross; Richard M. (Brandon, FL),
Monastyrskyi; Andrii (Tampa, FL), Flanigan; David L.
(Riverview, FL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Riscoe; Michael K.
Kelly; Jane X.
Winter; Rolf W.
Hinrichs; David J.
Smilkstein; Martin J.
Nilsen; Aaron
Burrows; Jeremy
Kyle; Dennis
Manetsch; Roman
Cross; Richard M.
Monastyrskyi; Andrii
Flanigan; David L. |
Tualatin
Lake Oswego
Portland
Lake Oswego
Portland
Portland
Eysins
Lithia
Tampa
Brandon
Tampa
Riverview |
OR
OR
OR
OR
OR
OR
N/A
FL
FL
FL
FL
FL |
US
US
US
US
US
US
CH
US
US
US
US
US |
|
|
Assignee: |
University of South Florida
(Tampa, FL)
Medicines for Malaria Venture (Geneva, CH)
|
Family
ID: |
47262888 |
Appl.
No.: |
13/153,350 |
Filed: |
June 3, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120115904 A1 |
May 10, 2012 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
PCT/US2009/066841 |
Dec 4, 2009 |
|
|
|
|
61201082 |
Dec 5, 2008 |
|
|
|
|
Current U.S.
Class: |
546/153 |
Current CPC
Class: |
C07D
401/12 (20130101); A61P 31/00 (20180101); C07D
215/42 (20130101); A61P 33/02 (20180101); C07D
403/06 (20130101); A61P 33/06 (20180101); C07D
401/04 (20130101); C07D 491/052 (20130101); C07D
279/16 (20130101); C07D 401/06 (20130101); A61P
31/04 (20180101); C07D 413/04 (20130101); C07D
215/233 (20130101); C07D 239/90 (20130101); C07D
403/04 (20130101); A61P 31/12 (20180101); C07D
215/60 (20130101); A61P 33/00 (20180101) |
Current International
Class: |
C07D
215/233 (20060101); A61P 33/06 (20060101); A61K
31/47 (20060101); A61P 31/00 (20060101); A61P
33/02 (20060101); A61P 33/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
551 029 |
|
May 1932 |
|
DE |
|
0 110 298 |
|
Jun 1984 |
|
EP |
|
0 332 033 |
|
Sep 1989 |
|
EP |
|
0 878 194 |
|
Nov 1998 |
|
EP |
|
1 386 914 |
|
Feb 2004 |
|
EP |
|
WO 2005/058834 |
|
Jun 2005 |
|
WO |
|
WO 2008/064011 |
|
May 2008 |
|
WO |
|
WO 2010/065905 |
|
Jun 2010 |
|
WO |
|
Other References
Boehme et al., Beta-Substituted enamines. VII. 3-Amino- and
3-mercapto-4(1H)-quinolones, 305(2) Archiv Der Pharmazie und
Berichte Der Deutschen Pharmazeutischen Gesellschaft 93-6 (1972).
cited by examiner .
Mullock et al., Synthetic uses of polyphosphoric acid and its ethyl
ester. II. Syntheses of indolin-2(3H)-ones and imidazoquinolines,
J. Chem. Soc. 2218-25 (1931). cited by examiner .
Massey et al., Action of nitric acid on polycyclic indole
derivatives. XI. Combined addition and substitution, J. Chem. Soc.
2218-25 (1931). cited by examiner .
Nishiwaki et al., Heterocyclizations of
2-aryl-3-arylamino-4,4,4-trifluoro-2-butenenitrile hydrates to
3-ary1-2-trifluoromethy1-4-quinolones and to
4-N-methylamino-3H-pyrazole-3-spiro-2'-(3'-ary1-3'-trifluoromethyl)oxiran-
es, 73(1) J. Fluorine Chem. 41-6 (1995). cited by examiner .
Kuznetsov et al., Approaches for Introducing High Molecular
Diversity in Scaffolds: Fast Parallel Synthesis of Highly
substituted 1H-Quinolin-4-one Libraries, 8(4) Molecular Diversity
437-448 (2004). cited by examiner .
Burckhalter & Mikolasek, Antimalarial agents. IX.
3-Alkylquinolones as Potential Repository Drugs, 56(2) J. Pharma.
Sci. 236-9 (1967). cited by examiner .
Adams et al., "The Iron Environment in Heme and Heme-Antimalarial
Complexes of Pharmacological Interest," Journal of Inorganic
Biochemistry 63:69-77, 1996. cited by applicant .
Ager, A.L. Jr., "Rodent Malaria Models," 68/1, Springer-Verlag,
Berlin, 1984. cited by applicant .
Ahmed et al., "A new rapid and simple non-radioactive assay to
monitor and determine the proliferation of lymphocytes: an
alternative to [.sup.3H]thymidine incorporation assay," Journal of
Immunological Methods 170:211-224, 1994. cited by applicant .
Ahua et al., "Antileishmanial and antifungal acridone derivatives
from the roots of Thamnosma rhodesica," Phytochemistry 65:963-868,
2004. cited by applicant .
Ambroise-Thomas, P., "Antimalarial vaccines. Disappointments and
hopes.,"Bull. Acad. Natl. Med. 181(8):1637-1650, Nov. 18, 1997.
(Abstract only). cited by applicant .
Anderson et al., "Parallel synthesis of 9-aminoacridines and their
evaluation against chloroquine-resistant Plasmodium falciparum,"
Bioorganic & Medicinal Chemistry 14(2):334-343, Jan. 15, 2006.
cited by applicant .
Atkinson et al., "Ultrastructure of Malaria-Infected Erythrocytes,"
Blood Cells 16:351-368, 1990. cited by applicant .
Bastow, K.F., "New Acridone Inhibitors of Human Herpes Virus
Replication," Current Drug Targets--Infectious Disorders
4(4):323-330, 2004. cited by applicant .
Bojang et al., "Follow-up of Gambian children recruited to a pilot
safety and immunogenicity study of the malaria vaccine SPf66,"
Parasite Immunology 19:579-581, 1997. cited by applicant .
Boudreau et al., "Tolerability of prophylactic Lariam.RTM.
regimens," Trop. Med. Parasitol. 44:257-265, 1993. cited by
applicant .
Brewer et al., "Neurotoxicity in animals due to arteether and
artemether," Transactions of the Royal Society of Tropical Medicine
and Hygiene 88(1):33-36, 1994. cited by applicant .
Brewer et al., "Factors Relating to Neurotoxicity or Artemisinin
Antimalarial Drugs <<Listening to Arteether>>," Me.d
Trop. 58(3):22S-27S, 1998. cited by applicant .
Broudy et al., "Moncytes Stimulate Fibroblastoid Bone Marrow
Stromal Cells to Produce Multilineage Hematopoietic Growth
Factors," Blood 65(2):530-534, Aug. 1986. cited by applicant .
Burckhalter et al., "Antimalarial Agents IX, 3-Alkylquinolones as
Potential Repository Drugs," Journal of Pharmaceutical Sciences
56(2):236-239, Feb. 1967. cited by applicant .
Carter & Mendis, "Evolutionary and Historical Aspects of the
Burden of Malaria," Clinical Microbiology Reviews 15(4):564-594,
Oct. 2002. cited by applicant .
Casey, A. "Synthesis of some 4-quinolones and related structures
for evaluation as potential antimalarial agents," University of
Bridgeport for Army Medical Research and Development Command, Nov.
30, 1974. cited by applicant .
Clark et al., "Developmental Toxicity of Artesunate and an
Artesunate Combination in the Rat and Rabbit," Birth Defects
Research (Part B) 71:380-394, 2004. cited by applicant .
Coleman et al., "Gametocytocidal and Sporontocidal Activity of
Antimalarials Against Plasmodium berghei Anka in ICR Mice and
Anopheles stephensi Mosquitoes," Am. J. Trop. Med. Hyg.
46(2):169-182, 1992. cited by applicant .
Croft et al., "The activity of hydroxynaphthoquinones against
Leishmania donovani," Journal of Antimicrobial Chemotherapy
30:827-832, 1992. cited by applicant .
Doolan et al., "DNA Vaccination as an Approach to Malaria Control:
Current Status and Strategies," Curr. Top. Microbiol. Immunol.
226:37-56, 1998. cited by applicant .
Fidock et al., "Antimalarial Drug Discovery: Efficacy Models for
Compound Screening," Nature Reviews 3:509-520, Jun. 2004. cited by
applicant .
Fivelman et al., "Modified Fixed-Ratio Isobologram Method for
Studying In Vitro Interactions between Atovaquone and Proguanil or
Dihydroartemisinin against Drug-Resistant Strains of Plasmodium
falciparum," Antimicrobial Agents and Chemotherapy
48(11):4097-4102, Nov. 2004. cited by applicant .
Fujioka et al., "Activities of New Acridone Alkaloid Derivatives
against Plasmodium yoelii in vitro,"Arzneim-Forsch/Drug Res.
40(11):1026-1029, 1990. cited by applicant .
Fusetti et al., "Meflochina ed ototossicita: descrizione di tre
casi," Clin Ter 150:379-382, 1999 (Abstract only). cited by
applicant .
Guillouzo, Andre, "Liver Cell Models in in Vitro Toxicology,"
Environmental Health Perspectives 106(7):511-532, Apr. 1998. cited
by applicant .
Hudson et al., "566C80: A Potent Broad Spectrum Anti-Infective
Agent with Activity Against Malaria and Opportunistic Infections in
AIDS Patients," Drugs Exptl. Clin. Res. 17(9):427-435, 1991. cited
by applicant .
Hudson, A.T., "Atovaquone--A Novel Broad-spectrum Anit-infective
Drug," Parasitology Today 9(2):66-68, 1993. cited by applicant
.
Ignatushchenko et al., "Xanthones as antimalarial agents; studies
of a possible mode of action," FEBS Letters 409:67-73, 1997. cited
by applicant .
Ignatushchenko et al., "Xanthones as Antimalarial Agents: Stage
Specificity," Am. J. Trop. Med. Hyg. 62(1):77-81, 2000. cited by
applicant .
Kelly et al., "A spectroscopic investigation of the binding
interactions between 4,5-dihydroxyxanthone and heme," Journal of
Inorganic Biochemistry 86:617-625, 2001. cited by applicant .
Kelly et al., "Optimization of Xanthones for Antimalarial Activity:
the 3,6-Bis-.omega.-Diethylaminoalkoxyxanthone Series,"
Antimicrobial Agents and Chemotherapy 46(1):144-150, Jan. 2002.
cited by applicant .
Kelly et al., "The kinetics of uptake and accumulation of
3,6-bis-.omega.-diethylamino-amyloxyxanthone by the human malaria
parasite Plasmodium falciparum," Molecular & Biochemical
Parasitology 123:47-54, 2002. cited by applicant .
Kelly et al., "Orally Active Acridones as Novel and Potent
Antimalarial Chemotypes," Abstract, ASTMH 55.sup.th Annual Meeting,
Atlanta, Georgia, 1 page (Nov. 12-16, 2006). cited by applicant
.
Kelly et al., "Structure-Activity Relationships of Orally Active
Antimalarial Acridones: Synthesis, Optimization, and Biological
Activity," Abstract, ASTMH 55.sup.th Annual Meeting, Atlanta,
Georgia, 1 page (Nov. 12-16, 2006). cited by applicant .
Kessl et al., "Molecular Basis for Atovaquone Resistance in
Pneumocystis jirovecii Modeled in the Cytochrome bc.sub.1 Complex
of Saccharomyces cerevisiae," The Journal of Biological Chemistry
279(4): 2817-2824, Jan. 23, 2004. cited by applicant .
Kessl et al., "Cytochrome b Mutations That Modify the
Ubiquinol-binding Pocket of the Cythochrome bc.sub.1 Complex and
Confer Anti-malarial Drug Resistance in Saccharomyces cerevisiae,"
The Journal of Biological Chemistry 280(17): 17142-17148, Feb. 17,
2005. cited by applicant .
Korsinczky et al., "Mutations in Plasmodium falciparum Cytochrome b
That Are Associated with Atovaquone Resistance Are Located at a
Putative Drug-Binding Site," Antimicrobial Agents and Chemotherapy
44(8):2100-2108, Aug. 2000. cited by applicant .
Krungkrai, J., "The multiple roles of the mitochondrion of the
malarial parasite," Parasitology 129:511-524, 2004. cited by
applicant .
Kyle et al., "Antimalarial Activity of 4(1H)-Quinolones," American
Society of Tropical Medicine and Hygiene 54.sup.th Annual Meeting,
Washington, D.C., USA, Dec. 11-15, 2005. cited by applicant .
Learngaramkul et al., "Molecular Characterization of Mitochondria
in Asexual and Sexual Blood Stages of Plasmodim falciparum,"
Molecular Cell Biology Research Communications 2:15-20, 1999. cited
by applicant .
Li et al., "Cryopreserved human hepatocytes: characterization of
drug-metabolizing enzyme activities and applications in higher
throughput screening assays for hepatotoxicity, metabolic
stability, and drug-drug interaction potential," Chemico-Biological
Interactions 121:17-35, 1999. cited by applicant .
Low, Lawrence K., "Metabolic Changes of Drugs and Related Organic
Compounds," Chapter 3, pp. 43-122 in J. N. Delgado and WA. Remers
(ed.), Wilson and Gisvold's Textbook of Organic Medicinal and
Pharmaceutical Chemistry, 10.sup.th edition, Raven Publishers,
Philadelphia, 1998. cited by applicant .
Lowden & Bastow, "Cell culture replication of herpes simplex
virus and, or human cytomegalovirus is inhibited by
3,7-dialkoxylated, 1-hydroxyacridone derivatives," Antiviral
Research 59:143-154, 2003. cited by applicant .
Luzzi and Peto, "Adverse Effects of Antimalarials; An Update," Drug
Safety 8(4):295-311, 1993. cited by applicant .
Madan et al., "Effect of Cryopreservation on Cytochrome P-450
Enzyme Induction in Cultured Rat Hepatocytes," Drug Metabolism and
Disposition 27(3):327-335, 1999. cited by applicant .
Makler et al., "Detection of Plasmodium falciparum Infection with
the Fluorescent Dye, Benzothiocarboxypurine," Am. J. Trop. Med.
Hyg. 44(1):11-16(90-191), 1991. cited by applicant .
Meshnick & Trumpower, "Multiple Cytochrome b Mutations May
Cause Atovaquone Resistance," JID Correspondence 191:822-823, Mar.
1, 2005. cited by applicant .
Michael, Joseph P., "Quinoline, quinazoline and acridone
alkaloids," Nat. Prod. Rep. 18:543-559, 2001. cited by applicant
.
Michael, Joseph P., "Quinoline, quinazoline and acridone
alkaloids," Nat. Prod. Rep. 20:476-493, 2003 (published online Aug.
19, 2003). cited by applicant .
Milhous, W.K., "Development of New Drugs for Chemoprophylaxis of
Malaria," Med. Trop. 61:48-50, 2001. cited by applicant .
Oettmeier et al., "Acridones and quinolones as inhibitors of
ubiquinone functions in the mitochondrial respiratory chain,"
Biochem Soc Trans. 22:213-216, 1994. cited by applicant .
Oettmeier et al., "Inhibition of electron transport through the
Q.sub.p site in cytochrome b/c.sub.1 complexes by acridones,"
Biochimica et Biophysica Acta 1188:125-130, 1994. cited by
applicant .
Olliaro & Yuthavong, "An Overview of Chemotherapeutic Targes
for Antimalarial Drug Discovery," Pharmacol. Ther. 81(2):91-110,
1999. cited by applicant .
Pessina et al., "In Vitro Tests for Haematotoxicity: Prediction of
Drug-induced Myelosuppression by the CFU-GM Assay," ATLA
30(Supplement 2):75-79, 2002. cited by applicant .
Pessina et al., "Application of the CFU-GM Assay to Predict Acute
Drug-Induced Neutropenia: An International Blind Trial to Validate
a Prediction Model for the Maxium Tolerated Dose (MTD) of
Myelosuppressive Xenobiotics," Toxicological Sciences 75:355-367,
2003. cited by applicant .
Peters et al., "The chemotherapy of rodent malaria, XXIII," Annals
of Tropical Medicine and Parasitology 69(3):311-328, 1975. cited by
applicant .
Phillips-Howard & ter Kuile, "CNS Adverse Events Associated
With Antimalarial Agents," Drug Safety 12(6):370-383, 1995. cited
by applicant .
Raether & Fink, "Antimalarial activity of Floxacrine (HOE 991)
I; Studies on blood schizontocidal action of Floxacrine against
Plasmodium berghei, P. vinckei and P. cynomologi," Annals of
Tropical Medicine and Parasitology 73(6):505-526, 1979. cited by
applicant .
Raether & Mehlhorn, "Action of a New Floxacrine Derivative (S
82 5455) on Asexual Stages of Plasmodium berghei: A Light and
Electron Microscopical Study," Zbl. Bakt. Hyg. A256:335-341, 1984.
cited by applicant .
Rathbun et al., "Interferon-.gamma.-induced apoptotic responses of
Fanconi anemia group C hematopoietic progenitor cells involve
caspase 8-dependent activation of caspase 3 family members," Blood
96(13):4204-4211, Dec. 15, 2000. cited by applicant .
Riscoe et al., "Evaluation and Lead Optimization of Antimalarial
Aromatic Ketones," Abstract, ASTMH 55.sup.th Annual Meeting,
Atlanta, Georgia, 1 page (Nov. 12-16, 2006). cited by applicant
.
Sachs & Malaney, "The economic and social burden of malaria,"
Nature 415:680-685, Feb. 7, 2002. cited by applicant .
Salzer et al., "Uber eine neuen, gegen Vogelmalaria wirksamen
Verbindungstypus," Chem. Ber. 81:12-19, 1948. cited by applicant
.
Schmidt, L.H., "Antimalarial Properties of Floxacrine, a
Dihydroacridinedione Derivative," Antimicrobial Agents and
Chemotherapy 16(4):475-485, Oct. 1979. cited by applicant .
Singh & Puri, "Interaction between chloroquine and diverse
pharmacological agents in chloroquine resistant Plasmodium yoelii
migeriensis," Acta Tropica 77:185-193, 2000. cited by applicant
.
Slomianny & Prensier, "A Cytochemical Ultrastructural Study of
the Lysosomal System of Different Species of Malaria Parasites," J.
Protozool. 37(6):465-470, Nov. 1990. cited by applicant .
Smilkstein et al., "Simple and Inexpensive Fluorescence-Based
Technique for High-Throughput Antimalarial Drug Screening,"
Antimicrobial Agents and Chemotherapy 48(5):1803-1806, May 2004.
cited by applicant .
Smilkstein et al., "Novel Antimalarial Acridone Derivatives with
Both Intrinsic Potency and Synergy with Selected Quinolines: In
Vitro and In Vivo Studies," Abstract, ASTMH 55.sup.th Annual
Meeting, Atlanta, Georgia, 1 page (Nov. 12-16, 2006). cited by
applicant .
Srivastava et al., "Atovaquone, a Broad Spectrum Antiparasitic
Drug, Collapses Mitochondrial Membrane Potential in a Malarial
Parasite," The Journal of Biological Chemistry 272(7):3961-3966,
1997. cited by applicant .
Srivastava et al., "Resistance mutations reveal the
atovaquone-binding domain of cytochrome b in malaria parasites,"
Molecular Microbiology 33(4):704-711, 1999. cited by applicant
.
Suswam et al., "Plasmodium falciparum: The Effects of Atovaquone
Resistance on Respiration," Experimental Parasitology 98:180-187,
2001. cited by applicant .
Taylor & White, "Antimalarial Drug Toxicity; A Review," Drug
Safety 27(1):25-61, 2004. cited by applicant .
Toovey & Jamieson, "Audiometric changes associated with the
treatment of uncomplicated falciparum malaria with co-artemether,"
Transactions of the Royal Societ of Tropical Medicine and Hygiene
98:261-267, 2004. cited by applicant .
Trouiller & Olliaro, "Drug Development Output from 1975 to
1996: What Proportion for Tropical Diseases?" Lancet 354:164-166,
1999. cited by applicant .
Trouiller & Olliaro, "Drug development output: what proportion
for tropical diseases?" Lancet 354:164-165, 1999. cited by
applicant .
Turker, M., "Estimation of mutation frequencies in normal mammalian
cells and the development of cancer," Cancer Biology 8:407-419,
1998. cited by applicant .
Vaidya & Mather, "Atovaquone resistance in malaria parasites,"
Drug Resistance Updates 3:283-287, 2000. cited by applicant .
Vaidya, A., "Mitochondrial Physiology as a Target for Atovaquone
and Other Antimalarials," I. Sherman (ed.), Malaria: Parasite
Biology, Pathogenesis, and Protection, American Society for
Microbiology, Washington, D.C. 355-368, 1996. cited by applicant
.
Varney et al., "Long-Term Neuropsychological Sequelae of Fever
Associated with Amnesia," Archives of Clinical Neuropsychology
9(4):347-352, 1994. cited by applicant .
Varney et al., "Neuropsychiatric Sequelae of Cerebral Malaria in
Vietnam Veterans," The Journal of Nervous and Mental Disease
185(11):695-703, 1997. cited by applicant .
Via et al., "Effects of cytokines on mycobacterial phagosome
maturation," Journal of Cell Science 111:897-905, Mar. 9, 1998.
cited by applicant .
Weina, P., "From Atabrine in World War II to Mefloquine in Somalia:
The Role of Education in Preventative Medicine," Military Medicine
163(9):635-639, 1998. cited by applicant .
White et al., "Averting a malaria disaster," The Lancet
353:1965-1967, Jun. 5, 1999. cited by applicant .
White, N., "Antimalarial drug resistance," The Journal of Clinical
Investigation 113(8):1084-1092, Apr. 2004. cited by applicant .
Williams, R. B., "The Mode of Action of Anticoccidial Quinolones
(6-Decyloxy-4-hydroxyquinoline-3-carboxylates) in Chickens,"
International Journal for Parasitology 27(1):101-111, 1997. cited
by applicant .
Winkelmann & Raether, "Antimalarial and Anticoccidial Activity
of 3-Aryl-7-chloro-3,4-dihydroacridine-1,9-(2H,10H)-diones,"
Arzneim-Forsch./Drug Res. 37(1):647-661, 1987. cited by applicant
.
Winter et al., "Hydroxy-Anthraquinones as Antimalarial Agents,"
Bioorganic & Medicinal Chemistry Letters 5(17):1927-1932, 1995.
cited by applicant .
Winter et al., "Potentiation of the Antimalarial Agent Rufigallol,"
Antimicrobial Agents and Chemotherapy 40(6):1408-1411, Jun. 1996.
cited by applicant .
Winter et al., "Potentiation of an Antimalarial Oxidant Drug,"
Antimicrobial Agents and Chemotherapy 41(7):1449-1454, Jul. 1997.
cited by applicant .
Winter et al., "Evaluation and lead optimization of anti-malarial
acridones," Experimental Parasitology 114:47-56, 2006. cited by
applicant .
Winter et al., "Antimalarial quinolones: Synthesis, potency, and
mechanistic studies," Experimental Parasitology 118:487-497, 2008
(Published online Nov. 7, 2007). cited by applicant .
Yeates et al., "Synthesis and Structure-Activity Relationships of
4-Pyridones as Potential Antimalarials," J. Med. Chem.
2008(51):2845-2852, 2008. cited by applicant .
International Search Reported from International Application No.
PCT/US2007/084560, dated Mar. 31, 2008. cited by applicant .
International Search Report from International Application No.
PCT/US2009/066841, dated Aug. 18, 2010. cited by applicant .
Written Opinion of the International Search Report from
International Application No. PCT/US2009/066841, dated Aug. 18,
2010. cited by applicant .
Non-Final Office action from corresponding U.S. Appl. No.
13/153,347 dated Aug. 2, 2012. cited by applicant .
Casey, "4(1H)-Quinolones. 2. Antimalarial Effect of Some
2-Methyl-3-(1'-alkenyl)- or-3-alkyl-4(1H)-quinolones," Journal of
Medicinal Chemistry 17:255-256, 1974. cited by applicant .
International Search Report and the Written Opinion of the
International Searching Authority from related PCT Application No.
PCT/US2012/040712 dated Jan. 30, 2013. cited by applicant.
|
Primary Examiner: Andres; Janet
Assistant Examiner: Rozof; Timothy R
Attorney, Agent or Firm: Klarquist Sparkman, LLP
Government Interests
ACKNOWLEDGMENT OF GOVERNMENT SUPPORT
The United States Government may have certain rights to
invention(s) disclosed herein as research that may be relevant to
the development of the invention was funded by United States
governmental grant funds from the United States Department of
Veteran Affairs Medical Research Program.
Parent Case Text
This is a continuation-in-part of International Application No.
PCT/US2009/066841, filed Dec. 4, 2009, which was published in
English under PCT Article 21(2), which in turn claims the benefit
of U.S. Provisional Application No. 61/201,082, filed on Dec. 5,
2008. Each of these is incorporated herein by reference in its
entirety.
Claims
What is claimed is:
1. A compound of formula I: ##STR00032## or formula II:
##STR00033## or a pharmaceutically acceptable salt of formula I or
formula II, wherein: R.sup.1 is H, hydroxyl, alkoxy, acyl, alkyl,
cycloalkyl, aryl, or heteroaryl; R.sup.2 is methyl, haloalkyl, or
heteroaryl; R.sup.4 is carbonyloxy or carbonyldioxy; R.sup.3 is a
diaryl ether; and R.sup.5 and R.sup.7 are each individually H,
halogen, alkoxy, alkyl, haloalkyl, aryl, nitro, cyano, amino,
amido, acyl, carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10,
wherein R.sup.10 is H, alkyl, amino or haloalkyl; R.sup.6 is H,
halogen, alkoxy, alkyl, haloalkyl, aryl, cyano, amino, amido, acyl,
carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10, wherein
R.sup.10 is H, alkyl, amino or haloalkyl; and R.sup.8 is H,
halogen, alkoxy, haloalkyl, aryl, nitro, cyano, amino, amido, acyl,
carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10, wherein
R.sup.10 is H, alkyl, amino or haloalkyl; provided that in formula
I, R.sup.6 is not H or methoxy; and in formula II that if R.sup.4
is carbonyldioxy then R.sup.7 is not methoxy.
2. The compound of claim 1, wherein R.sup.5 and R.sup.7 of formula
I or II are each halogen or haloalkyl.
3. The compound of claim 1, wherein R.sup.5 and R.sup.7 of formula
I or II are each F.
4. The compound of claim 1, wherein R.sup.4 is carbonyloxy or
carbonyldioxy.
5. The compound of claim 1, wherein R.sup.7 of formula I or II is
not methoxy.
6. The compound of claim 1, wherein R.sup.6 of formula I or II is
halogen and R.sup.5 and R.sup.7 are each H.
7. The compound of claim 1, wherein R.sup.2 of formula I or II is
methyl.
8. The compound of claim 1, wherein R.sup.1 is H, alkyl, or
cycloalkyl.
9. The compound of claim 1, wherein the compound of formula II has
a structure represented by formula III: ##STR00034## wherein
R.sup.9 is alkyl, alkenyl, alkyl amino, amido, aminocarbonyl,
hydroxyalkyl, alkoxyalkyl or alkyl ether.
10. The compound of claim 1, wherein the compound of formula II has
a structure represented by formula IV: ##STR00035## wherein R.sup.9
is alkyl, alkenyl, alkyl amino, amido, aminocarbonyl, hydroxyalkyl,
alkoxyalkyl or alkyl ether.
11. The compound of claim 1, wherein the compound is a compound of
formula I.
12. The compound of claim 1, wherein R.sup.7 is methoxy.
13. The compound of claim 1, wherein R.sup.6 is halogen.
14. The compound of claim 1, wherein R.sup.3 is ##STR00036##
wherein R.sup.13 and R.sup.14 are each individually selected from
at least one of alkoxy, halogen-substituted alkoxy, halogenated
lower alkyl, alkyl, methylsulfonyl, or halogen; c is 0 to 5; and d
is 0 to 5.
15. The compound of claim 1, wherein R.sup.1 is H; R.sup.2 is
methyl; R.sup.6 is halogen; R.sup.7 is H or methoxy; and R.sup.5
and R.sup.8 are each H.
16. A compound of formula XI: ##STR00037## or a pharmaceutically
acceptable salt of formula XI, wherein: R.sup.1 is H; R.sup.2 is
methyl; R.sup.3 is an optionally substituted diaryl ether R.sup.6
is halogen; R.sup.7 is H or methoxy; and R.sup.5 and R.sup.8 are
each H.
17. The compound of claim 16, wherein R.sup.3 is ##STR00038##
wherein R.sup.13 and R.sup.14 are each individually selected from
at least one of alkoxy, halogen-substituted alkoxy, halogenated
lower alkyl, alkyl, methylsulfonyl, or halogen; c is 0 to 5; and d
is 0 to 5.
18. A compound, or a pharmaceutically acceptable salt thereof,
having a structure of: ##STR00039##
19. A compound, or a pharmaceutically acceptable salt thereof,
having a structure of: ##STR00040##
20. The compound of claim 1, or a pharmaceutically acceptable salt
thereof, having a structure of: ##STR00041##
21. A composition comprising a pharmacologically active amount of
at least one compound of claim 1 or a pharmaceutically acceptable
salt thereof, and at least one pharmaceutically acceptable
carrier.
22. A composition comprising a pharmacologically active amount of
at least one compound of claim 18 or a pharmaceutically acceptable
salt thereof, and at least one pharmaceutically acceptable
carrier.
23. The composition according to claim 21, further comprising at
least one further antimalarial agent.
24. The composition according to claim 23, wherein the further
antimalarial agent is selected from quinine, chloroquine,
atovaquone, proguanil, primaquine, amodiaquine, mefloquine,
piperaquine, artemisinin, methylene blue, pyrimethamine,
sulfadoxine, artemether-lumefantrine, dapsone-chlorproguanil,
artesunate, quinidine, clopidol, pyridine/pyridinol analogs,
4(1H)-quinolone analogs, dihydroartemisinin, a mixture of
atovaquone and proguanil, an endoperoxide, an acridone, a
pharmachin or any combination of these.
25. The composition according to claim 22, further comprising at
least one further antimalarial agent.
26. A compound of formula XI: ##STR00042## or a pharmaceutically
acceptable salt of formula XI, wherein: R.sup.1 is H, hydroxyl,
alkoxy, acyl, alkyl, cycloalkyl, aryl, or heteroaryl; R.sup.2 is H,
carboxyl, substituted carboxyl, alkyl, haloalkyl, or heteroaryl;
R.sup.5, R.sup.7 and R.sup.8 are each individually H, halogen,
alkoxy, alkyl, haloalkyl, aryl, nitro, cyano, amino, amido, acyl,
carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10, wherein
R.sup.10 is H, alkyl, amino or haloalkyl; R.sup.6 is halogen; and
R.sup.3 is an optionally substituted diaryl ether.
27. The compound of claim 17, wherein c is 1.
28. The compound of claim 14, wherein c is 1.
29. A compound of formula I: ##STR00043## or a pharmaceutically
acceptable salt of formula I, wherein: R.sup.1 is H, hydroxyl,
alkoxy, acyl, alkyl, cycloalkyl, aryl, or heteroaryl; R.sup.2 is
methyl, haloalkyl, or heteroaryl; R.sup.3 is
trifluoromethoxy-diarylether; and R.sup.5, R.sup.6, and R.sup.7 and
R.sup.8 are each individually H, halogen, alkoxy, alkyl, haloalkyl,
aryl, nitro, cyano, amino, amido, acyl, carboxyl, substituted
carboxyl, or --SO.sub.2R.sup.10, wherein R.sup.10 is H, alkyl,
amino or haloalkyl; provided that in formula I, R.sup.5 and R.sup.7
are not both H or R.sup.6 is not H or methoxy.
30. A compound of formula I: ##STR00044## or a pharmaceutically
acceptable salt of formula I, wherein: R.sup.1 is H, hydroxyl,
alkoxy, acyl, alkyl, cycloalkyl, aryl, or heteroaryl; R.sup.2 is
methyl, haloalkyl, or heteroaryl; R.sup.3 is ##STR00045## wherein
R.sup.13 and R.sup.14 are each individually selected from at least
one of alkoxy, halogen-substituted alkoxy, halogenated lower alkyl,
alkyl, methylsulfonyl, or halogen; c is 0 to 5; and d is 0 to 5;
and R.sup.5, R.sup.6, and R.sup.7 and R.sup.8 are each individually
H, halogen, alkoxy, alkyl, haloalkyl, aryl, nitro, cyano, amino,
amido, acyl, carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10,
wherein R.sup.10 is H, alkyl, amino or haloalkyl; provided that in
formula I, R.sup.5 and R.sup.7 are not both H or R.sup.6 is not H
or methoxy.
31. A compound of formula I: ##STR00046## or a pharmaceutically
acceptable salt of formula I, wherein: R.sup.1 is H, hydroxyl,
alkoxy, acyl, alkyl, cycloalkyl, aryl, or heteroaryl; R.sup.2 is
methyl, haloalkyl, or heteroaryl; R.sup.3 is
trifluoromethoxy-diarylether; and R.sup.5 and R.sup.7 are each
individually H, halogen, alkoxy, alkyl, haloalkyl, aryl, nitro,
cyano, amino, amido, acyl, carboxyl, substituted carboxyl, or
--SO.sub.2R.sup.10, wherein R.sup.10 is H, alkyl, amino or
haloalkyl; R.sup.6 is H, halogen, alkoxy, alkyl, haloalkyl, aryl,
cyano, amino, amido, acyl, carboxyl, substituted carboxyl, or
--SO.sub.2R.sup.10, wherein R.sup.10 is H, alkyl, amino or
haloalkyl; and R.sup.8 is H, halogen, alkoxy, haloalkyl, aryl,
nitro, cyano, amino, amido, acyl, carboxyl, substituted carboxyl,
or --SO.sub.2R.sup.10, wherein R.sup.10 is H, alkyl, amino or
haloalkyl; provided that in formula I, R.sup.6 is not H or
methoxy.
32. The compound of claim 31, wherein R.sup.7 is methoxy.
33. The compound of claim 31, wherein R.sup.6 is halogen.
34. A composition comprising a pharmacologically active amount of
at least one compound of claim 30 or a pharmaceutically acceptable
salt thereof, and at least one pharmaceutically acceptable
carrier.
35. The composition according to claim 34, further comprising at
least one further antimalarial agent.
Description
FIELD
The compounds and composition disclosed herein relate to inhibiting
infectious and parasitic diseases, particularly malaria and
toxoplasmosis.
BACKGROUND
Diseases caused by organisms of the phylum Apicomplexa include
malaria, toxoplasmosis and coccidiosis.
Malaria is a tropical disease, spread by mosquitoes from person to
person, that exacts a devastating toll in endemic regions,
especially Africa, where it claims 1 to 2 million lives each year.
The deaths occur primarily among young children and pregnant
women-vulnerable populations for whom therapeutic options are
limited. These options are even more restricted in the current
landscape of widespread drug resistance in the Plasmodium parasites
that cause malaria. Together with an increasing incidence of
malaria worldwide, there is an urgent and unmet need for new drugs
to prevent and treat malaria, an infection that causes clinical
disease manifestations in 300 to 500 million people each year.
Malaria is a worsening global health problem. The incidence of
malaria continues to increase worldwide, due in part to the
emergence of drug resistance but also due to global warming.
Initially observed in the late 1950's and early 1960's in South
America and Southeast Asia, chloroquine-resistant Plasmodium
parasites that are associated with the most virulent form of
malaria, cerebral malaria, have now spread to all malarious regions
of the world. Varney et al. (1994) (1997) and others report a
strong correlation between cerebral malaria and neuropsychiatric
symptoms, such as poor dichotic listening, `personality change`,
depression, and, in some cases, partial seizure-like symptoms. The
tropical neuralnesia resulting from the legendary malarial fevers
is well known in the endemic areas and has been documented
throughout history.
Chloroquine replacement drugs are urgently needed to treat and
prevent malaria. The endoperoxides, like artemisinin (derived from
a Chinese herbal remedy extracted from the wormwood plant) are
being used in other parts of the world for malaria therapy.
However, the use of this remedy is limited by reports of
ototoxicity and neurotoxic effects of the endoperoxides. More
recently, severe reproductive toxicity in female rats has been
reported in animals treated with artesunate and its active
metabolite, dihydroartemisinin. These findings are mirrored in
reports by others in several different animal models.
While the great panacea for malaria therapy would be the
development of a long-lasting vaccine, the failure of the SPf66
vaccine and unrealized potential of newer multi-component DNA
vaccines, combine to indicate that a vaccine is a long way from
reality. As a result, the need continues to exist in the medical
field for the development of safe, inexpensive anti-parasitic
agents, especially agents that are useful against
multi-drug-resistant organisms such as P. falciparum and P.
vivax.
Toxoplasmosis, caused by Toxoplasma gondii, is a leading cause of
birth defects and it is estimated that the health care costs due to
toxoplasmosis are roughly 5 billion dollars each year in the United
States. In addition, there are researchers who believe that latent
toxoplasmosis infections may underlie certain mental illness
conditions including schizophrenia.
Hans Andersag is well known for the discovery of chloroquine
(resochin) in the 1930's. He was also connected with the discovery
of "endochin", a compound that elicited great interest among Bayer
scientists because of its efficacy in treatment and prevention of
malaria in a bird model (P. cathemerium/canary) of the disease. In
subsequent work summarized by Kikuth and Mudrow-Reichenow, Steck,
and Wiselogle, endochin also demonstrated efficacy in treatment and
prophylaxis against P. gallinaceum in the chick and P. lophurae in
the turkey. Kikuth further reported that endochin exerted
gametocidal action against male gametocytes undergoing
exflagellation in finches infected with Haemoproteus, a closely
related member of the Apicomplexa. Despite these unique and
desirable qualities, endochin's antimalarial potential was never
realized because it failed to cure malaria infections in subsequent
experiments in mammalian species ranging from mice to non-human
primates (Rhesus monkeys).
SUMMARY
Disclosed herein are compounds of formula I:
##STR00003##
or formula II:
##STR00004##
or a pharmaceutically acceptable salt of formula I or formula II,
wherein:
R.sup.1 is H, hydroxyl, alkoxy, acyl, alkyl, cycloalkyl, aryl, or
heteroaryl;
R.sup.2 is methyl, haloalkyl, or heteroaryl;
R.sup.4 is hydroxyl, carbonyloxy, or carbonyldioxy;
R.sup.3 is aliphatic, aryl, aralkyl, or alkylaryl; and
R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each individually H,
halogen, alkoxy, alkyl, haloalkyl, aryl, nitro, cyano, amino,
amido, acyl, carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10,
wherein R.sup.10 is H, alkyl, amino or haloalkyl;
provided that in formula I, R.sup.5 and R.sup.7 are not H or
R.sup.6 is not H or methoxy; and in formula II that if R.sup.4 is
carbonyldioxy then R.sup.7 is not methoxy.
Also disclosed herein are compositions comprising a
pharmacologically active amount of at least one compound of formula
I or II, or a pharmaceutically acceptable salt thereof, and at
least one pharmaceutically acceptable carrier.
Further disclosed herein are methods for inhibiting a parasitic or
infectious disease in a subject comprising administering to the
subject a therapeutically effective amount of a compound of formula
I or II, or a pharmaceutically acceptable salt thereof.
The foregoing will become more apparent from the following detailed
description, which proceeds with reference to the accompanying
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a general reaction scheme for synthesizing compounds
disclosed herein.
FIG. 2 is a reaction scheme for a specific compound disclosed
herein.
FIG. 3 is a reaction scheme for ELQ-125, a prodrug ester, which is
another specific compound disclosed herein.
7-Difluoro-3-heptyl-2-methyl-4(1H)-quinolone (ELQ-121) is
deprotonated with sodium hydride in an aprotic polar solvent such
as tetrahydrofuran and then reacted with a chloroformate ester of
the appropriate polyethylene glycol monomethylether. In the
reaction illustrated in FIG. 3, the chloroformate of tetraglyme
monomethylether, is obtained by reacting carbonyl chloride with
tetraglyme monomethylether.
FIG. 4 is a table listing compounds and their activity against
Plasmodium falciparum strains in vitro.
FIG. 5 is a table listing compounds and their activity against
Toxoplasma gondii in vitro.
FIG. 6 is an example of an additional reaction scheme for
synthesizing compounds disclosed herein.
FIG. 7 is an example of an additional reaction scheme for
synthesizing compounds disclosed herein.
FIG. 8 is an example of an additional reaction scheme for
synthesizing compounds disclosed herein.
FIG. 9 shows illustrative compounds.
FIG. 10 shows illustrative compounds.
FIG. 11 shows illustrative compounds.
FIG. 12 shows illustrative compounds.
FIG. 13 shows illustrative compounds.
FIG. 14 shows illustrative compounds.
FIG. 15 shows illustrative compounds.
FIG. 16 shows illustrative compounds.
DETAILED DESCRIPTION
The following explanations of terms and methods are provided to
better describe the present compounds, compositions and methods,
and to guide those of ordinary skill in the art in the practice of
the present disclosure. It is also to be understood that the
terminology used in the disclosure is for the purpose of describing
particular embodiments and examples only and is not intended to be
limiting.
As used herein, the singular terms "a," "an," and "the" include
plural referents unless context clearly indicates otherwise. Also,
as used herein, the term "comprises" means "includes." Hence
"comprising A or B" means including A, B, or A and B.
Variables such as R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5,
R.sup.6, R.sup.7, R.sup.8, R.sup.9, n, X and Y, used throughout the
disclosure are the same variables as previously defined unless
stated to the contrary.
The term "acyl" refers group of the formula RC(O)-- wherein R is an
organic group.
"Administration of" and "administering a" compound should be
understood to mean providing a compound, a prodrug of a compound,
or a pharmaceutical composition as described herein. The compound
or composition can be administered by another person to the subject
(e.g., intravenously) or it can be self-administered by the subject
(e.g., tablets).
The term "aliphatic" is defined as including alkyl, alkenyl,
alkynyl, halogenated alkyl and cycloalkyl groups as described
above. A "lower aliphatic" group is a branched or unbranched
aliphatic group having from 1 to 10 carbon atoms.
"Alkanediyl" or "cycloalkanediyl" refers to a divalent radical of
the general formula --C.sub.nH.sub.2n-derived from aliphatic or
cycloaliphatic hydrocarbons.
The term "alkenyl" refers to a hydrocarbon group of 2 to 24 carbon
atoms and structural formula containing at least one carbon-carbon
double bond. A "lower alkenyl" group has 1 to 10 carbon atoms.
The term "alkyl" refers to a branched or unbranched saturated
hydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, hexyl,
heptyl, octyl, decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl
and the like, A "lower alkyl" group is a saturated branched or
unbranched hydrocarbon having from 1 to 10 carbon atoms. Preferred
alkyl groups have 1 to 4 carbon atoms. Alkyl groups may be
"substituted alkyls" wherein one or more hydrogen atoms are
substituted with a substituent such as halogen, cycloalkyl, alkoxy,
amino, hydroxyl, aryl, or carboxyl.
The term "alkyl amino" refers to alkyl groups as defined above
where at least one hydrogen atom is replaced with an amino
group.
The term "alkynyl" refers to a hydrocarbon group of 2 to 24 carbon
atoms and a structural formula containing at least one
carbon-carbon triple bond.
The term "alkoxy" refers to a straight, branched or cyclic
hydrocarbon configuration and combinations thereof, including from
1 to 20 carbon atoms, preferably from 1 to 8 carbon atoms, more
preferably from 1 to 4 carbon atoms, that include an oxygen atom at
the point of attachment. An example of an "alkoxy group" is
represented by the formula --OR, where R can be an alkyl group,
optionally substituted with an alkenyl, alkynyl, aryl, aralkyl,
cycloalkyl, halogenated alkyl, or heterocycloalkyl group as
described above. Suitable alkoxy groups include methoxy, ethoxy,
n-propoxy, i-propoxy, n-butoxy, i-butoxy, sec-butoxy, tert-butoxy
cyclopropoxy, cyclohexyloxy, and the like.
"Alkoxycarbonyl" refers to an alkoxy substituted carbonyl radical,
--C(O)OR, wherein R represents an optionally substituted alkyl,
aryl, aralkyl, cycloalkyl, cycloalkylalkyl or similar moiety.
The term "amine" or "amino" refers to a group of the formula
--NRR', where R and R' can be, independently, hydrogen or an alkyl,
alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, halogenated alkyl, or
heterocycloalkyl group described above.
"Aminocarbonyl" alone or in combination, means an amino substituted
carbonyl (carbamoyl) radical, wherein the amino radical may
optionally be mono- or di-substituted, such as with alkyl, aryl,
aralkyl, cycloalkyl, cycloalkylalkyl, alkanoyl, alkoxy carbonyl,
aralkoxycarbonyl and the like. An aminocarbonyl group may be
--N(R)--C(O)--R (wherein R is a substituted group or H) or
--C(O)--N(R). An "aminocarbonyl" is inclusive of an amido group. A
suitable aminocarbonyl group is acetamido.
The term "amide" or "amido" is represented by the formula
--C(O)NRR', where R and R' independently can be a hydrogen, alkyl,
alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, halogenated alkyl, or
heterocycloalkyl group described above. A suitable amido group is
acetamido.
The term "aralkyl" refers to an aryl group having an alkyl group,
as defined above, attached to the aryl group, as defined above. An
example of an aralkyl group is a benzyl group.
The term "aryl" refers to any carbon-based aromatic group
including, but not limited to, benzene, naphthalene, etc. The term
"aryl" also includes "heteroaryl group," which is defined as an
aromatic group that has at least one heteroatom incorporated within
the ring of the aromatic group. Examples of heteroatoms include,
but are not limited to, nitrogen, oxygen, sulfur, and phosphorous.
The aryl group can be substituted with one or more groups
including, but not limited to, alkyl, alkynyl, alkenyl, aryl,
halide, nitro, amino, ester, ketone, aldehyde, hydroxy, carboxylic
acid, or alkoxy, or the aryl group can be unsubstituted.
"Carbonyl" refers to a radical of the formula --C(O)--.
Carbonyl-containing groups include any substituent containing a
carbon-oxygen double bond (C.dbd.O), including acyl groups, amides,
carboxy groups, esters, ureas, carbamates, carbonates and ketones
and aldehydes, such as substituents based on --COR or --RCHO where
R is an aliphatic, heteroaliphatic, alkyl, heteroalkyl, hydroxyl,
or a secondary, tertiary, or quaternary amine.
"Carboxyl" refers to a --COON radical. Substituted carboxyl refers
to --COOR where R is aliphatic, heteroaliphatic, alkyl,
heteroalkyl, or a carboxylic acid or ester.
The term "cycloalkyl" refers to a non-aromatic carbon-based ring
composed of at least three carbon atoms. Examples of cycloalkyl
groups include, but are not limited to, cyclopropyl, cyclobutyl,
cyclopentyl, cyclohexyl, and the like. The term "heterocycloalkyl
group" is a cycloalkyl group as defined above where at least one of
the carbon atoms of the ring is substituted with a heteroatom such
as, but not limited to, nitrogen, oxygen, sulfur, or
phosphorous.
"Derivative" refers to a compound or portion of a compound that is
derived from or is theoretically derivable from a parent
compound.
"Equipotency" refers to the capacity of the inventive compounds
disclosed herein to inhibit the growth of parasites, especially
drug-resistant Plasmodium parasites, with roughly the same power or
capacity (e.g., with a range of 2 to 3-fold), regardless of the
level of intrinsic resistance to chloroquine, quinine, or other
antimalarial agents.
The terms "halogenated alkyl" or "haloalkyl group" refer to an
alkyl group as defined above with one or more hydrogen atoms
present on these groups substituted with a halogen (F, Cl, Br,
I).
The term "hydroxyl" is represented by the formula --OH.
The term "hydroxyalkyl" refers to an alkyl group that has at least
one hydrogen atom substituted with a hydroxyl group. The term
"alkoxyalkyl group" is defined as an alkyl group that has at least
one hydrogen atom substituted with an alkoxy group described
above.
"Inhibiting" (which is inclusive of "treating") refers to
inhibiting the full development of a disease or condition, for
example, in a subject who is at risk for a disease such as malaria.
"Treatment" refers to a therapeutic intervention that ameliorates a
sign or symptom of a disease or pathological condition after it has
begun to develop. As used herein, the term "treating," with
reference to a disease, pathological condition or symptom, also
refers to any observable beneficial effect of the treatment. The
beneficial effect can be evidenced, for example, by a delayed onset
of clinical symptoms of the disease in a susceptible subject, a
reduction in severity of some or all clinical symptoms of the
disease, a slower progression of the disease, a reduction in the
number of relapses of the disease, an improvement in the overall
health or well-being of the subject, or by other parameters well
known in the art that are specific to the particular disease,
"Inhibiting" also refers to any quantitative or qualitative
reduction including prevention of infection or complete killing of
an invading organism, relative to a control. A "prophylactic"
treatment is a treatment administered to a subject who does not
exhibit signs of a disease or exhibits only early signs for the
purpose of decreasing the risk of developing pathology. By the term
"coadminister" is meant that each of at least two compounds be
administered during a time frame wherein the respective periods of
biological activity overlap. Thus, the term includes sequential as
well as coextensive administration of two or more drug
compounds.
"Invading" relates to a pathological activity of an organism
against a healthy cell, a population of healthy cells, or whole
organism.
"Multidrug-resistant" or "drug-resistant" refers to malaria, or the
parasites causing malaria, that have developed resistance to
treatment by at least one therapeutic agent historically
administered to treat malaria. For example, there are
multidrug-resistant strains of Plasmodium falciparum that harbor
high-level resistance to chloroquine, quinine, mefloquine,
pyrimethamine, sulfadoxine and atovaquone.
Optionally substituted groups, such as "optionally substituted
alkyl," refers to groups, such as an alkyl group, that when
substituted, have from 1-5 substituents, typically 1, 2 or 3
substituents, selected from alkoxy, optionally substituted alkoxy,
acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, aryl,
carboxyalkyl, optionally substituted cycloalkyl, optionally
substituted cycloalkenyl, halogen, optionally substituted
heteroaryl, optionally substituted heterocyclyl, hydroxy, sulfonyl,
thiol and thioalkoxy. In particular, optionally substituted alkyl
groups include, by way of example, haloalkyl groups, such as
fluoroalkyl groups, including, without limitation, trifluoromethyl
groups.
"Optional" or "optionally" means that the subsequently described
event or circumstance can but need not occur, and that the
description includes instances where said event or circumstance
occurs and instances where it does not.
The terms "pharmaceutically acceptable salt" or "pharmacologically
acceptable salt" refers to salts prepared by conventional means
that include basic salts of inorganic and organic acids, including
but not limited to hydrochloric acid, hydrobromic acid, sulfuric
acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid,
malic acid, acetic acid, oxalic acid, tartaric acid, citric acid,
lactic acid, fumaric acid, succinic acid, maleic acid, salicylic
acid, benzoic acid, phenylacetic acid, mandelic acid and the like.
"Pharmaceutically acceptable salts" of the presently disclosed
compounds also include those formed from cations such as sodium,
potassium, aluminum, calcium, lithium, magnesium, zinc, and from
bases such as ammonia, ethylenediamine, N-methyl-glutamine, lysine,
arginine, ornithine, choline, N,N'-dibenzylethylenediamine,
chloroprocaine, diethanolamine, procaine, N-benzylphenethylamine,
diethylamine, piperazine, tris(hydroxymethyl)aminomethane, and
tetramethylammonium hydroxide. These salts may be prepared by
standard procedures, for example by reacting the free acid with a
suitable organic or inorganic base. Any chemical compound recited
in this specification may alternatively be administered as a
pharmaceutically acceptable salt thereof. "Pharmaceutically
acceptable salts" are also inclusive of the free acid, base, and
zwitterionic forms. Descriptions of suitable pharmaceutically
acceptable salts can be found in Handbook of Pharmaceutical Salts,
Properties, Selection and Use, Wiley VCH (2002). When compounds
disclosed herein include an acidic function such as a carboxy
group, then suitable pharmaceutically acceptable cation pairs for
the carboxy group are well known to those skilled in the art and
include alkaline, alkaline earth, ammonium, quaternary ammonium
cations and the like. Such salts are known to those of skill in the
art. For additional examples of "pharmacologically acceptable
salts," see Berge et al., J. Pharm. Sci. 66:1 (1977).
The term "pharmacologically active amount" relates to an amount of
a compound that provides a detectable reduction in parasitic
activity in vitro or in vivo, or diminishes the likelihood of
emergence of drug resistance.
"Saturated or unsaturated" includes substituents saturated with
hydrogens, substituents completely unsaturated with hydrogens and
substituents partially saturated with hydrogens.
The term "subject" includes both human and veterinary subjects.
A "therapeutically effective amount" or "diagnostically effective
amount" refers to a quantity of a specified agent sufficient to
achieve a desired effect in a subject being treated with that
agent. For example, this may be the amount of a compound disclosed
herein useful in detecting or treating thyroid cancer in a subject.
Ideally, a therapeutically effective amount or diagnostically
effective amount of an agent is an amount sufficient to inhibit or
treat the disease without causing a substantial cytotoxic effect in
the subject. The therapeutically effective amount or diagnostically
effective amount of an agent will be dependent on the subject being
treated, the severity of the affliction, and the manner of
administration of the therapeutic composition.
Prodrugs of the disclosed compounds also are contemplated herein. A
prodrug is an active or inactive compound that is modified
chemically through in vivo physiological action, such as
hydrolysis, metabolism and the like, into an active compound
following administration of the prodrug to a subject. The
suitability and techniques involved in making and using prodrugs
are well known by those skilled in the art. For a general
discussion of prodrugs involving esters see Svensson and Tunek Drug
Metabolism Reviews 165 (1988) and Bundgaard Design of Prodrugs,
Elsevier (1985).
The term "prodrug" also is intended to include any covalently
bonded carriers that release an active parent drug of the present
invention in vivo when the prodrug is administered to a subject.
Since prodrugs often have enhanced properties relative to the
active agent pharmaceutical, such as, solubility and
bioavailability, the compounds disclosed herein can be delivered in
prodrug form. Thus, also contemplated are prodrugs of the presently
disclosed compounds, methods of delivering prodrugs and
compositions containing such prodrugs. Prodrugs of the disclosed
compounds typically are prepared by modifying one or more
functional groups present in the compound in such a way that the
modifications are cleaved, either in routine manipulation or in
vivo, to yield the parent compound. Prodrugs include compounds
having a phosphonate and/or amino group functionalized with any
group that is cleaved in vivo to yield the corresponding amino
and/or phosphonate group, respectively. Examples of prodrugs
include, without limitation, compounds having an acylated amino
group and/or a phosphonate ester or phosphonate amide group. In
particular examples, a prodrug is a lower alkyl phosphonate ester,
such as an isopropyl phosphonate ester.
Protected derivatives of the disclosed compounds also are
contemplated. A variety of suitable protecting groups for use with
the disclosed compounds are disclosed in Greene and Wuts Protective
Groups in Organic Synthesis; 3rd Ed.; John Wiley & Sons, New
York, 1999.
In general, protecting groups are removed under conditions which
will not affect the remaining portion of the molecule. These
methods are well known in the art and include acid hydrolysis,
hydrogenolysis and the like. One preferred method involves the
removal of an ester, such as cleavage of a phosphonate ester using
Lewis acidic conditions, such as in TMS-Br mediated ester cleavage
to yield the free phosphonate. A second preferred method involves
removal of a protecting group, such as removal of a benzyl group by
hydrogenolysis utilizing palladium on carbon in a suitable solvent
system such as an alcohol, acetic acid, and the like or mixtures
thereof. A t-butoxy-based group, including t-butoxy carbonyl
protecting groups can be removed utilizing an inorganic or organic
acid, such as HCl or trifluoroacetic acid, in a suitable solvent
system, such as water, dioxane and/or methylene chloride. Another
exemplary protecting group, suitable for protecting amino and
hydroxy functions amino is trityl. Other conventional protecting
groups are known and suitable protecting groups can be selected by
those of skill in the art in consultation with Greene and Wuts
Protective Groups in Organic Synthesis; 3rd Ed.; John Wiley &
Sons, New York, 1999.
When an amine is deprotected, the resulting salt can readily be
neutralized to yield the free amine. Similarly, when an acid
moiety, such as a phosphonic acid moiety is unveiled, the compound
may be isolated as the acid compound or as a salt thereof.
Particular examples of the presently disclosed compounds include
one or more asymmetric centers; thus these compounds can exist in
different stereoisomeric forms. Accordingly, compounds and
compositions may be provided as individual pure enantiomers or as
stereoisomeric mixtures, including racemic mixtures. In certain
embodiments the compounds disclosed herein are synthesized in or
are purified to be in substantially enantiopure form, such as in a
90% enantiomeric excess, a 95% enantiomeric excess, a 97%
enantiomeric excess or even in greater than a 99% enantiomeric
excess, such as in enantiopure form.
It is understood that substituents and substitution patterns of the
compounds described herein can be selected by one of ordinary skill
in the art to provide compounds that are chemically stable and that
can be readily synthesized by techniques known in the art and
further by the methods set forth in this disclosure. Reference will
now be made in detail to the presently preferred compounds.
The following abbreviations are used herein: ED.sub.50--effective
drug concentration required to decrease parasitemia by 50% relative
to control, untreated animals; FACS--fluorescence activated cells
sorting/scanning; Gavage--oral route of drug administration;
IC.sub.50--drug concentration required to inhibit parasite growth
by 50% relative to control values; i.p.--intraperitoneal;
i.v.--intravenous; IVTI--in vitro therapeutic index; calculated
from the ratio of IC.sub.50 value based on the cytotoxicity
observed in the blastogenesis assay and the anti-malarial potency
against the D6 strain (non-drug resistant, drug sensitive) of P.
falciparum. MSF--malaria specific fluorescence assay;
PRBC--parasitized red blood cell(s); RFU--relative fluorescence
units
Compounds
Examples of the compounds disclosed herein exhibit equipotent
activity against multidrug-resistant strains of Plasmodium
parasites and may be of use in treating both the liver and blood
stages of malaria as well as other infectious and/or parasitic
diseases of humans and animals. Antimalarial drugs targeting the
liver stage offer many advantages over drugs that merely target the
blood stage. First, drugs active against the liver stage represent
true causally prophylactic agents that can prevent all disease
symptoms, including death, associated with malaria. Secondly, it
has been established that while wild-caught mosquitoes may harbor
thousands of sporozoites, only .apprxeq.10 sporozoites are
transferred in a single bite to the human host. Over the next 2-3
weeks the sporozoite reproduces in the liver to produce
10,000-30,000 descendants before the schizont ruptures and
parasites flood into the bloodstream where the absolute parasite
burden may increase to ten thousand billion (10.sup.13) circulating
plasmodia. Clearly it is advantageous to strike at the liver stage
where parasite numbers are low, to diminish the likelihood of
selecting for a drug resistant mutant and before the infection has
a chance to weaken the defenses of the human host. The compounds
described herein may block sporozoite-induced infections in humans,
due to their enhanced metabolic stability in the human system, a
feature that endochin lacks. As a result, the compounds can be used
prophylactically to prevent malaria due to their ability to
interfere with parasite development in the liver stage of malaria
infection in humans.
In examples of the compounds disclosed herein, the quinolone
nucleus has been modified to enhance metabolic stability and
incorporate additional structural changes that endow the compounds
with potent intrinsic activity against aminoquinoline-, antifol-,
and atovaquone-resistant parasites (IC.sub.50's in the low to
sub-nanomolar range), low cytotoxicity toward mammalian cells
(IC.sub.50's>50 .mu.M) and with the therapeutic power to clear a
robust P. yoelii infection in mice by the oral route of
administration. The compounds may exhibit many desirable
characteristics of therapeutic molecules: MW.sub.(parent
molecule)<500, log P<5, achiral, tolerance to extremes of
temperature, ease of synthesis, low cost of materials, scaleable
chemical procedures, high level of potency, oral bioavailability,
parenteral option for drug delivery, once-daily dosing 3-day
curative regimen, lack of cytotoxicity, lack of observable whole
animal toxicity, and the potential for targeting multiple
developmental stages of the parasite life cycle in humans.
In the compounds of formula I, R.sup.1 may be H, hydroxyl, alkoxy,
acyl, alkyl, cycloalkyl, aryl, or heteroaryl. In certain
embodiments, R.sup.1 may be H or alkyl (e.g., a branched, linear or
cyclic alkyl having 1 to 10 carbon atoms). In some examples,
compounds wherein R.sup.1 is an alkyl are particularly useful for
treating toxoplasmosis.
In the compounds of formula I or II, R.sup.2 may be methyl or
haloalkyl (e.g., --CF.sub.3), particularly methyl.
In the compounds of formula I or II, R.sup.3 may be aliphatic,
aryl, aralkyl, or alkylaryl. For example, R.sup.3 may be
cycloalkyl, hetero-cycloalkyl, aliphatic ether,
trifluoromethoxy-aliphatic ether, arahaloalkyl,
trifluoromethoxy-diarylether, alkyl-heteroaryl, or
alkyl-halogenated heteroaryl. Illustrative aliphatic groups include
branched, linear or cyclic alkyl or heteroalkyl, or branched or
linear alkenyl, particularly alkyl or alkenyl groups having 3 to 12
carbon atoms. In one embodiment, the alkyl or alkenyl is
substituted at its terminal end with one or more fluorine atoms.
Illustrative terminal moieties include --CH.sub.2F, --CHF.sub.2,
--CF.sub.3, --C.sub.2F.sub.5, -n-C.sub.3F.sub.7, -i-C.sub.3F.sub.7,
-n-C.sub.4F.sub.9, -i-C.sub.4F.sub.9, or --SF.sub.5. R.sup.3 also
may be terminated in trifluoromethoxy. In an additional embodiment,
R.sup.3 is 3-methyl-butyl or 3-methyl-but-2-enyl. In another
embodiment, R.sup.3 is a heterocycloalkyl or a heteroaryl. In a
further embodiment, R.sup.3 is heptyl or fluorine-terminated
heptyl.
In certain embodiments that may provide enhanced bioavailability,
metabolic stability and/or aqueous solubility, R.sup.3 of formula I
or II may be an optionally substituted cycloalkyl, optionally
substituted heterocycloalkyl or an optionally substituted
heteroaryl. The cycloalkyl may be cyclohexyl. In certain
embodiments, the heterocycloalkyl or heteroaryl are 5- or
6-membered rings that include at least one N and/or O heteroatom.
Illustrative heterocycloalkyls include pyrrolidinyl and
piperidinyl. Illustrative heteroaryls include pyrrolyl, furanyl,
pyranyl, imidazolyl, pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl,
pyridazinyl and isoxazolyl. In certain embodiments, the
heterocycloalkyl or heteroaryl includes a single heteroatom (e.g.,
N or O) that is in the 4' position relative to the attachment point
of the heterocycloalkyl to the quinolone. The cycloalkyl,
heterocycloalkyl or heteroaryl may be substituted with alkoxy (e.g.
lower alkoxy), halogen-substituted alkoxy (e.g. lower alkoxy),
halogenated lower alkyl, alkyl and/or halogen.
Formulae V-VII below are examples of structures wherein R.sup.3 is
an optionally substituted cycloalkyl, optionally substituted
heterocycloalkyl or an optionally substituted heteroaryl:
##STR00005##
wherein R.sup.11 is C or a heteroatom that may be at any position
on the ring; a is 3 to 6 (e.g., the ring may contain 0 to 4
heteroatoms); R.sup.12 is selected from at least one of alkoxy
(e.g. lower alkoxy), halogen-substituted alkoxy (e.g. lower alkoxy
such as trifluoromethoxy), halogenated lower alkyl, alkyl or
halogen; and b is 0 to 5;
##STR00006##
wherein R.sup.11 is a heteroatom and R.sup.12 is the same as in
formula V; or
##STR00007##
wherein R.sup.11 is a heteroatom and R.sup.12 is the same as in
formula V.
In other embodiments that may provide enhanced bioavailability,
metabolic stability and/or aqueous solubility, R.sup.3 of formula I
or II may be an optionally substituted alkynyl (e.g., an
aryl-substituted alkynyl). In certain instances, the alkynyl is
ethynyl or a substituted ethynyl. Illustrative substituted ethynyls
include an aryl-substituted alkynyl such as phenylethynyl,
ethynylpyridine, or ethynylpyrimidine. The aryl ring of the
aryl-substituted alkynyl may itself be substituted. Illustrative
substituents include alkoxy (e.g. lower alkoxy),
halogen-substituted alkoxy (e.g. lower alkoxy), halogenated lower
alkyl, alkyl and halogen. The aryl group of the aryl-substituted
alkynyl may also be a heterocycloalkyl or heteroaryl as described
above.
Formulae VIII-IX below are examples of compounds wherein R.sup.3 is
an aryl-substituted alkynyl:
##STR00008##
wherein R.sup.11 is C or a heteroatom that may be at any position
on the ring; a is 3 to 6 (e.g., the ring may contain 0 to 4
heteroatoms); R.sup.12 is selected from at least one of alkoxy
(e.g. lower alkoxy), halogen-substituted alkoxy (e.g. lower alkoxy
such as trifluoromethoxy), halogenated lower alkyl, alkyl or
halogen; and b is 0 to 5; or
##STR00009##
wherein R.sup.11 is a heteroatom, a is 1; and R.sup.12 is the same
as in formula VIII.
In a further embodiment that may provide enhanced bioavailability,
metabolic stability and/or aqueous solubility, R.sup.3 of formula I
or II may be an optionally substituted diarylether. Either one or
both of the aryl rings may be substituted phenyl or heteroaryl such
as pyridyl or pyrimidyl. Illustrative substituents include alkoxy
(e.g. lower alkoxy), halogen-substituted alkoxy (e.g. lower alkoxy
such as trifluoromethoxy), halogenated lower alkyl, alkyl,
methylsulfonyl and halogen.
Formula X below is an example of wherein R.sup.3 is an optionally
substituted diphenylether:
##STR00010##
wherein R.sup.13 and R.sup.14 are each individually selected from
at least one of alkoxy (e.g. lower alkoxy), halogen-substituted
alkoxy (e.g. lower alkoxy such as trifluoromethoxy), halogenated
lower alkyl, alkyl and halogen; c is 0 to 5; and d is 0 to 5. In
certain embodiments, d is 1 to 4 (preferably d is 1) and R.sup.14
is a halogen (particularly F). In certain embodiments, c is 1 to 5
(preferably c is 1) and R.sup.13 is a halogen-substituted alkoxy
(e.g. lower alkoxy such as trifluoromethoxy).
In the compounds of formula II, R.sup.4 may be hydroxyl,
carbonyloxy, or carbonyldioxy. "Carbonyloxy" refers to a divalent
structure of the formula --O--C(O)--R.sup.9, and "carbonyldioxy"
refers to a divalent structure of the formula
--O--C(O)--O--R.sup.9, wherein R.sup.9 is alkyl, alkenyl, alkyl
amino, amido, aminocarbonyl, hydroxyalkyl, alkoxyalkyl or alkyl
ether. For example, R.sup.4 may be a promoiety obtained via
esterification of an oxo or hydroxyl group at the 4-position of a
precursor compound. In particular, R.sup.4 may be an ester or
carbonate ester of an organic acid (e.g., succinate, acetate or
fumarate), an amino acid (e.g., glycinate), a polyhydric alcohol
(e.g., polyethylene glycol or ethylene glycol) or a polyether. For
instance, certain compounds have a structure represented by formula
III:
##STR00011##
or a structure represented by formula IV:
##STR00012##
R.sup.5, R.sup.6, R.sup.7 and R.sup.8 of formula I or II may be
each individually H, halogen, alkoxy, alkyl, haloalkyl, aryl,
nitro, cyano, amino, amido, acyl, carboxyl, substituted carboxyl,
or --SO.sub.2R.sup.10, wherein R.sup.10 is H, alkyl, amino or
haloalkyl. In certain embodiments, --SO.sub.2R.sup.10 is
--SO.sub.2CH.sub.3, --SO.sub.2NH.sub.2, or --SO.sub.2CF.sub.3. In
other examples, R.sup.5 and R.sup.7 are not H, and are, in
particular, halogen or haloalkyl. In one specific embodiment
R.sup.5 and R.sup.7 are each fluorine and, optionally, R.sup.6 and
R.sup.8 are each H. In another specific embodiment, R.sup.6 is not
H (e.g., R.sup.6 is halogen (particularly chloro or fluoro),
haloalkyl, cyano, etc.) and R.sup.5, R.sup.7 and R.sup.8 are each
H. In a further specific embodiment, R.sup.6 is halogen. In a
further specific embodiment, R.sup.7 is methoxy. In another
specific embodiment, R.sup.6 is fluoro and R.sup.7 is methoxy.
In particular embodiments of formula I, R.sup.1 is H or lower
alkyl; R.sup.2 is methyl; R.sup.3 is branched, linear or cycloalkyl
or branched or linear alkenyl; R.sup.5 and R.sup.7 are each
fluorine; and R.sup.6 and R.sup.8 are each H.
In a further particular embodiment of formula I, R.sup.1 is H;
R.sup.2 is H or methyl (preferably methyl); R.sup.3 is cycloalkyl,
heterocycloalkyl, heteroaryl, alkynyl or diaryl ether; R.sup.6 is
halogen; R.sup.7 is H or methoxy; and R.sup.5 and R.sup.8 are each
H. More specifically, the R.sup.3 group has the structure of any
one of formulae V-X above. Even more specifically, R.sup.3 is
pyrrolidinyl, piperidinyl, pyrrolyl, furanyl, pyranyl, imidazolyl,
pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl,
isoxazolyl, aryl-substituted ethynyl, or diphenyl ether.
In particular embodiments of formula II, R.sup.1 is H or lower
alkyl; R.sup.2 is methyl; R.sup.3 is branched, linear or cycloalkyl
or branched or linear alkenyl; R.sup.4 is carbonyloxy or
carbonyldioxy; and R.sup.7 is not methoxy.
Also disclosed herein are compounds of formula XI:
##STR00013##
or a pharmaceutically acceptable salt of formula XI, wherein:
R.sup.1 is H, hydroxyl, alkoxy, acyl, alkyl, cycloalkyl, aryl, or
heteroaryl;
R.sup.2 is H, carboxyl, substituted carboxyl, alkyl, haloalkyl, or
heteroaryl;
R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each individually H,
halogen, alkoxy, alkyl, haloalkyl, aryl, nitro, cyano, amino,
amido, acyl, carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10,
wherein R.sup.10 is H, alkyl, amino or haloalkyl; and
R.sup.3 is an optionally substituted cycloalkyl, an optionally
substituted heterocycloalkyl, an optionally substituted heteroaryl,
an optionally substituted alkynyl or an optionally substituted
diaryl ether.
In certain embodiments, the R.sup.3 group for formula XI has the
structure of any one of formulae V-X above.
In a further particular embodiment of formula XI, R.sup.1 is H;
R.sup.2 is H or methyl (preferably methyl); R.sup.6 is halogen;
R.sup.7 is H or methoxy; and R.sup.5 and R.sup.8 are each H. In
specific embodiments, R.sup.3 is pyrrolidinyl, piperidinyl,
pyrrolyl, furanyl, pyranyl, imidazolyl, pyrazolyl, pyridinyl,
pyrazinyl, pyrimidinyl, pyridazinyl, isoxazolyl, aryl-substituted
ethynyl, or diphenyl ether.
In certain embodiment, formulae I-XI disclosed above are inclusive
of oxo-quinolone-N-oxide analogs thereof.
General methods used in preparation of 4(1H)-quinolones and
prodrugs of them. The method utilizes the Conrad-Limpach reaction
(see FIG. 1), which consists of condensing a substituted (position
2) acetoacetic ester with an aniline, which provides a
2-substituted-3-phenylamino crotonic ester (alternatively
formulated as a Schiff base) and is followed by ring-closure in a
high-boiling solvent, e.g., Dowtherm A, (atm. p) at
.apprxeq.250.degree. C., a mixture of 73.5% diphenylether and 26.5%
biphenyl, to form the desired quinolone. This method allows for
reliable syntheses of quinolones varying in substitution pattern on
the benzenoid ring and varying in the length and nature of the
substituent group at the 3-position. Once the core 4(1H)-quinolone
is synthesized and purified further modifications can be made to
enhance activity or physical chemical properties that in turn
enhance drug delivery.
More particularly, the Conrad-Limpach synthesis of substituted
quinolones (shown in FIG. 1) which requires the condensation of a
meso- (=2-) substituted acetoacetic ester with an aniline, followed
by condensation of the intermediate 3-anilinocrotonic ester [Walter
Salzer, Helmut Timmler, Hans Andersag, Uber einen neuen, gegen
Vogelmalaria wirksamen Verbindungstypus, Chem. Ber. 81, 12 (1948)]
at .apprxeq.250.degree. C. This condensation is most conveniently
carried out in a stable solvent boiling at that temperature. Useful
for this purpose are, e.g. 2-chloro-naphthalene, a mixture of 73.5%
diphenyl ether and 26.5% diphenyl (Dowtherm A) or hydrocarbons
boiling at that temperature. Dowtherm A was used throughout. An
alternative procedure that is useful for heat-sensitive
substituents consists of cyclizing the intermediate
3-anilinocrotonic ester by heating with phosphoroxy trichloride to
produce a 4-chloroquinoline which may be hydrolyzed to the
corresponding 4-quinolone [Gerhard Buchmann, Wolfgang Grimm, J.
prakt. Chemie, 17, 135 (1962)].
Certain examples of the compounds may be made by a Suzuki coupling
reaction as shown in FIG. 6. Miyaura et al., Tetrahedron letters
1979 Vol. 20 Issue 36, pp 3437-3440. Potential advantages of the
Suzuki method are (1) higher yield from more reactive iodide, (2)
simplified purification, ethyl acetate/hexane chromatography, (3)
quinolone crystallizes out of solution during deprotection
reaction.
According to another embodiment, certain examples of the compounds
may be made by a Sonogashira reaction sequence as shown in FIG. 7.
Sonogashira et al., Tetrahedron letters 16 (50): 4467-4470. A
further synthesis scheme is shown in FIG. 8 for introducing an
isopropyl group at the 2-position.
Composition and Methods
The compounds and pharmaceutical compositions disclosed herein can
be used for inhibiting or preventing parasitic diseases. For
example, human or animal parasitic diseases include malaria,
toxoplasmosis, amebiasis, giardiasis, leishmaniasis,
trypanosomiasis, and coccidiosis, caused by organisms such as
Toxoplasma sp., Eimeria sp., Babesia bovis, Theileria sp., and also
includes infections by helminths, such as ascaris, schistosomes and
filarial worms. The compounds and compositions are also effective
in the inhibition of fungal pathogens including Pneumocystis
carinii, Aspergillus fumigatus, and others.
In particular embodiments, the parasitic diseases may be caused by
parasites that cause malaria. Particular species of parasites that
are included within this group include all species that are capable
of causing human or animal infection. Illustrative species include
Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale,
Plasmodium knowlesi, and Plasmodium malariae. The compounds and
compositions disclosed herein are particularly useful for
inhibiting drug-resistant malaria such as chloroquine-resistant
malaria or multidrug-resistant malaria that is caused by organisms
harboring resistance to chloroquine, quinine, mefloquine,
pyrimethamine, dapsone, and/or atovaquone.
Toxoplasmosis is caused by a sporozoan parasite of the Apicomplexa
called Toxoplasma gondii. It a common tissue parasite of humans and
animals. Most of the infections appear to be asymptomatic (90%),
however toxoplasmosis poses a serious health risk for
immuno-compromised individuals, such as organ transplant
recipients, cancer and AIDS patients, and the unborn children of
infected mothers. The compounds disclosed herein may be used alone
to treat toxoplasmosis or they may be co-administered with
"antifolates" such as sulfonamides, pyrimethamine, tirmethoprim,
biguanides and/or atovaquone.
In further embodiments, the compounds disclosed herein may be
co-administered with another pharmaceutically active compound. For
example, the compounds may be co-administered with quinine,
chloroquine, atovaquone, proguanil, primaquine, amodiaquine,
mefloquine, piperaquine, artemisinin, methylene blue,
pyrimethamine, sulfadoxine, artemether-lumefantrine (Coartem.RTM.),
dapsone-chlorproguanil (LAPDAP.RTM.), artesunate, quinidine,
clopidol, pyridine/pyridinol analogs, 4(1H)-quinolone analogs,
dihydroartemisinin, a mixture of atovaquone and proguanil, an
endoperoxide, an acridone as disclosed in WO 2008/064011 (which is
incorporated herein by reference in its entirety), a pharmachin as
disclosed in U.S. Provisional Patent Application titled "Compounds
for Treating Parasitic Disease" filed Nov. 18, 2008 (which is
incorporated herein by reference in its entirety), or any
combination of these.
The compounds disclosed herein may be included in pharmaceutical
compositions (including therapeutic and prophylactic formulations),
typically combined together with one or more pharmaceutically
acceptable vehicles or carriers and, optionally, other therapeutic
ingredients (for example, antibiotics, anti-inflammatories, or
drugs that are used to reduce pruritus such as an antihistamine).
The compositions disclosed herein may be advantageously combined
and/or used in combination with other antimalarial agents as
described above.
Such pharmaceutical compositions can be administered to subjects by
a variety of mucosal administration modes, including by oral,
rectal, intranasal, intrapulmonary, or transdermal delivery, or by
topical delivery to other surfaces. Optionally, the compositions
can be administered by non-mucosal routes, including by
intramuscular, subcutaneous, intravenous, intra-arterial,
intra-articular, intraperitoneal, intrathecal,
intracerebroventricular, or parenteral routes. In other alternative
embodiments, the compound can be administered ex vivo by direct
exposure to cells, tissues or organs originating from a
subject.
To formulate the pharmaceutical compositions, the compound can be
combined with various pharmaceutically acceptable additives, as
well as a base or vehicle for dispersion of the compound. Desired
additives include, but are not limited to, pH control agents, such
as arginine, sodium hydroxide, glycine, hydrochloric acid, citric
acid, and the like. In addition, local anesthetics (for example,
benzyl alcohol), isotonizing agents (for example, sodium chloride,
mannitol, sorbitol), adsorption inhibitors (for example, Tween 80
or Miglyol 812), solubility enhancing agents (for example,
cyclodextrins and derivatives thereof), stabilizers (for example,
serum albumin), and reducing agents (for example, glutathione) can
be included. Adjuvants, such as aluminum hydroxide (for example,
Amphogel, Wyeth Laboratories, Madison, N.J.), Freund's adjuvant,
MPL.TM. (3-O-deacylated monophosphoryl lipid A; Corixa, Hamilton,
Ind.) and IL-12 (Genetics Institute, Cambridge, Mass.), among many
other suitable adjuvants well known in the art, can be included in
the compositions. When the composition is a liquid, the tonicity of
the formulation, as measured with reference to the tonicity of 0.9%
(w/v) physiological saline solution taken as unity, is typically
adjusted to a value at which no substantial, irreversible tissue
damage will be induced at the site of administration. Generally,
the tonicity of the solution is adjusted to a value of about 0.3 to
about 3.0, such as about 0.5 to about 2.0, or about 0.8 to about
1.7.
The compound can be dispersed in a base or vehicle, which can
include a hydrophilic compound having a capacity to disperse the
compound, and any desired additives. The base can be selected from
a wide range of suitable compounds, including but not limited to,
copolymers of polycarboxylic acids or salts thereof, carboxylic
anhydrides (for example, maleic anhydride) with other monomers (for
example, methyl (meth)acrylate, acrylic acid and the like),
hydrophilic vinyl polymers, such as polyvinyl acetate, polyvinyl
alcohol, polyvinylpyrrolidone, cellulose derivatives, such as
hydroxymethylcellulose, hydroxypropylcellulose and the like, and
natural polymers, such as chitosan, collagen, sodium alginate,
gelatin, hyaluronic acid, and nontoxic metal salts thereof. Often,
a biodegradable polymer is selected as a base or vehicle, for
example, polylactic acid, poly(lactic acid-glycolic acid)
copolymer, polyhydroxybutyric acid, poly(hydroxybutyric
acid-glycolic acid) copolymer and mixtures thereof. Alternatively
or additionally, synthetic fatty acid esters such as polyglycerin
fatty acid esters, sucrose fatty acid esters and the like can be
employed as vehicles. Hydrophilic polymers and other vehicles can
be used alone or in combination, and enhanced structural integrity
can be imparted to the vehicle by partial crystallization, ionic
bonding, cross-linking and the like. The vehicle can be provided in
a variety of forms, including fluid or viscous solutions, gels,
pastes, powders, microspheres and films for direct application to a
mucosal surface.
The compound can be combined with the base or vehicle according to
a variety of methods, and release of the compound can be by
diffusion, disintegration of the vehicle, or associated formation
of water channels. In some circumstances, the compound is dispersed
in microcapsules (microspheres) or nanocapsules (nanospheres)
prepared from a suitable polymer, for example, isobutyl
2-cyanoacrylate (see, for example, Michael et al., J. Pharmacy
Pharmacol. 43:1-5, 1991), and dispersed in a biocompatible
dispersing medium, which yields sustained delivery and biological
activity over a protracted time.
The compositions of the disclosure can alternatively contain as
pharmaceutically acceptable vehicles substances as required to
approximate physiological conditions, such as pH adjusting and
buffering agents, tonicity adjusting agents, wetting agents and the
like, for example, sodium acetate, sodium lactate, sodium chloride,
potassium chloride, calcium chloride, sorbitan monolaurate, and
triethanolamine oleate. For solid compositions, conventional
nontoxic pharmaceutically acceptable vehicles can be used which
include, for example, pharmaceutical grades of mannitol, lactose,
starch, magnesium stearate, sodium saccharin, talcum, cellulose,
glucose, sucrose, magnesium carbonate, and the like.
Pharmaceutical compositions for administering the compound can also
be formulated as a solution, microemulsion, or other ordered
structure suitable for high concentration of active ingredients.
The vehicle can be a solvent or dispersion medium containing, for
example, water, ethanol, polyol (for example, glycerol, propylene
glycol, liquid polyethylene glycol, and the like), and suitable
mixtures thereof. Proper fluidity for solutions can be maintained,
for example, by the use of a coating such as lecithin, by the
maintenance of a desired particle size in the case of dispersible
formulations, and by the use of surfactants. In many cases, it will
be desirable to include isotonic agents, for example, sugars,
polyalcohols, such as mannitol and sorbitol, or sodium chloride in
the composition. Prolonged absorption of the compound can be
brought about by including in the composition an agent which delays
absorption, for example, monostearate salts and gelatin.
In certain embodiments, the compound can be administered in a time
release formulation, for example in a composition which includes a
slow release polymer. These compositions can be prepared with
vehicles that will protect against rapid release, for example a
controlled release vehicle such as a polymer, microencapsulated
delivery system or bioadhesive gel. Prolonged delivery in various
compositions of the disclosure can be brought about by including in
the composition agents that delay absorption, for example, aluminum
monostearate hydrogels and gelatin. When controlled release
formulations are desired, controlled release binders suitable for
use in accordance with the disclosure include any biocompatible
controlled release material which is inert to the active agent and
which is capable of incorporating the compound and/or other
biologically active agent. Numerous such materials are known in the
art. Useful controlled-release binders are materials that are
metabolized slowly under physiological conditions following their
delivery (for example, at a mucosal surface, or in the presence of
bodily fluids). Appropriate binders include, but are not limited
to, biocompatible polymers and copolymers well known in the art for
use in sustained release formulations. Such biocompatible compounds
are non-toxic and inert to surrounding tissues, and do not trigger
significant adverse side effects, such as nasal irritation, immune
response, inflammation, or the like. They are metabolized into
metabolic products that are also biocompatible and easily
eliminated from the body.
Exemplary polymeric materials for use in the present disclosure
include, but are not limited to, polymeric matrices derived from
copolymeric and homopolymeric polyesters having hydrolyzable ester
linkages. A number of these are known in the art to be
biodegradable and to lead to degradation products having no or low
toxicity. Exemplary polymers include polyglycolic acids and
polylactic acids, poly(DL-lactic acid-co-glycolic acid),
poly(D-lactic acid-co-glycolic acid), and poly(L-lactic
acid-co-glycolic acid). Other useful biodegradable or bioerodable
polymers include, but are not limited to, such polymers as
poly(epsilon-caprolactone), poly(epsilon-aprolactone-CO-lactic
acid), poly(epsilon.-aprolactone-CO-glycolic acid),
poly(beta-hydroxy butyric acid), poly(alkyl-2-cyanoacrilate),
hydrogels, such as poly(hydroxyethyl methacrylate), polyamides,
poly(amino acids) (for example, L-leucine, glutamic acid,
L-aspartic acid and the like), poly(ester urea),
poly(2-hydroxyethyl DL-aspartamide), polyacetal polymers,
polyorthoesters, polycarbonate, polymaleamides, polysaccharides,
and copolymers thereof. Many methods for preparing such
formulations are well known to those skilled in the art (see, for
example, Sustained and Controlled Release Drug Delivery Systems, J.
R. Robinson, ed., Marcel Dekker, Inc., New York, 1978). Other
useful formulations include controlled-release microcapsules (U.S.
Pat. Nos. 4,652,441 and 4,917,893), lactic acid-glycolic acid
copolymers useful in making microcapsules and other formulations
(U.S. Pat. Nos. 4,677,191 and 4,728,721) and sustained-release
compositions for water-soluble peptides (U.S. Pat. No.
4,675,189).
The pharmaceutical compositions of the disclosure typically are
sterile and stable under conditions of manufacture, storage and
use. Sterile solutions can be prepared by incorporating the
compound in the required amount in an appropriate solvent with one
or a combination of ingredients enumerated herein, as required,
followed by filtered sterilization. Generally, dispersions are
prepared by incorporating the compound and/or other biologically
active agent into a sterile vehicle that contains a basic
dispersion medium and the required other ingredients from those
enumerated herein. In the case of sterile powders, methods of
preparation include vacuum drying and freeze-drying which yields a
powder of the compound plus any additional desired ingredient from
a previously sterile-filtered solution thereof. The prevention of
the action of microorganisms can be accomplished by various
antibacterial and antifungal agents, for example, parabens,
chlorobutanol, phenol, sorbic acid, thimerosal, and the like.
In accordance with the various treatment methods of the disclosure,
the compound can be delivered to a subject in a manner consistent
with conventional methodologies associated with management of the
disorder for which treatment or prevention is sought. In accordance
with the disclosure herein, a prophylactically or therapeutically
effective amount of the compound and/or other biologically active
agent is administered to a subject in need of such treatment for a
time and under conditions sufficient to prevent, inhibit, and/or
ameliorate a selected disease or condition or one or more
symptom(s) thereof.
Typical subjects intended for treatment with the compositions and
methods of the present disclosure include humans, as well as
non-human primates and other animals. To identify subjects for
prophylaxis or treatment according to the methods of the
disclosure, accepted screening methods are employed to determine
risk factors associated with a parasitic infection to determine the
status of an existing disease or condition in a subject. These
screening methods include, for example, preparation of a blood
smear from an individual suspected of having malaria. The blood
smear is then fixed in methanol and stained with Giemsa and
examined microscopically for the presence of Plasmodium infected
red blood cells. These and other routine methods allow the
clinician to select patients in need of therapy using the methods
and pharmaceutical compositions of the disclosure.
The administration of the compound of the disclosure can be for
either prophylactic or therapeutic purpose. When provided
prophylactically, the compound is provided in advance of any
symptom. The prophylactic administration of the compound serves to
prevent or ameliorate any subsequent disease process. When provided
therapeutically, the compound is provided at (or shortly after) the
onset of a symptom of disease or infection.
For prophylactic and therapeutic purposes, the compound can be
administered to the subject by the oral route or in a single bolus
delivery, via continuous delivery (for example, continuous
transdermal, mucosal or intravenous delivery) over an extended time
period, or in a repeated administration protocol (for example, by
an hourly, daily or weekly, repeated administration protocol). The
therapeutically effective dosage of the compound can be provided as
repeated doses within a prolonged prophylaxis or treatment regimen
that will yield clinically significant results to alleviate one or
more symptoms or detectable conditions associated with a targeted
disease or condition as set forth herein. Determination of
effective dosages in this context is typically based on animal
model studies followed up by human clinical trials and is guided by
administration protocols that significantly reduce the occurrence
or severity of targeted disease symptoms or conditions in the
subject. Suitable models in this regard include, for example,
murine, rat, avian, porcine, feline, non-human primate, and other
accepted animal model subjects known in the art. Alternatively,
effective dosages can be determined using in vitro models (for
example, whole cell assays that monitor the effect of various drugs
on parasite growth rate). Using such models, only ordinary
calculations and adjustments are required to determine an
appropriate concentration and dose to administer a therapeutically
effective amount of the compound (for example, amounts that are
effective to elicit a desired immune response or alleviate one or
more symptoms of a targeted disease). In alternative embodiments,
an effective amount or effective dose of the compound may simply
inhibit or enhance one or more selected biological activities
correlated with a disease or condition, as set forth herein, for
either therapeutic or diagnostic purposes.
The actual dosage of the compound will vary according to factors
such as the disease indication and particular status of the subject
(for example, the subject's age, size, fitness, extent of symptoms,
susceptibility factors, and the like), time and route of
administration, other drugs or treatments being administered
concurrently, as well as the specific pharmacology of the compound
for eliciting the desired activity or biological response in the
subject. Dosage regimens can be adjusted to provide an optimum
prophylactic or therapeutic response. A therapeutically effective
amount is also one in which any toxic or detrimental side effects
of the compound and/or other biologically active agent is
outweighed in clinical terms by therapeutically beneficial effects.
A non-limiting range for a therapeutically effective amount of a
compound and/or other biologically active agent within the methods
and formulations of the disclosure is about 0.01 mg/kg body weight
to about 20 mg/kg body weight, such as about 0.05 mg/kg to about 5
mg/kg body weight, or about 0.2 mg/kg to about 2 mg/kg body
weight.
Dosage can be varied by the attending clinician to maintain a
desired concentration at a target site (for example, the lungs or
systemic circulation). Higher or lower concentrations can be
selected based on the mode of delivery, for example,
trans-epidermal, rectal, oral, pulmonary, or intranasal delivery
versus intravenous or subcutaneous delivery. Dosage can also be
adjusted based on the release rate of the administered formulation,
for example, of an intrapulmonary spray versus powder, sustained
release oral versus injected particulate or transdermal delivery
formulations, and so forth.
The instant disclosure also includes kits, packages and
multi-container units containing the herein described
pharmaceutical compositions, active ingredients, and/or means for
administering the same for use in the prevention and treatment of
diseases and other conditions in mammalian subjects. Kits for
diagnostic use are also provided. In one embodiment, these kits
include a container or formulation that contains one or more of the
conjugates described herein. In one example, this component is
formulated in a pharmaceutical preparation for delivery to a
subject. The conjugate is optionally contained in a bulk dispensing
container or unit or multi-unit dosage form. Optional dispensing
means can be provided, for example a pulmonary or intranasal spray
applicator. Packaging materials optionally include a label or
instruction indicating for what treatment purposes and/or in what
manner the pharmaceutical agent packaged therewith can be used.
EXAMPLES
FIG. 2 depicts the reaction sequence for preparation of ELQ-121 by
the Conrad-Limpach approach.
Synthesis of 2-Methyl-3-(n-heptyl)-5.7-difluorquinolone
(ELQ-121)
Ethyl 2-n-heptylacetoacetate (10.0 g, 43.9 mmol),
3.5-difluoroaniline (5.67 g, 43.9 mmol), 200 ml benzene and 0.20 g
p-toluenesulfonic acid monohydrate are heated in a flask fitted
with a water separator for 20 hours; more acid (0.30 g) is added
and water removal continued for 3 more days. Solvent is removed
(rotary evaporator) and the residue dropped quickly into 15 ml of
boiling Dowtherm A, kept at boiling temperature for 5 minutes and
allowed to cool. The product crystallizes out upon cooling. After
one and one-half hours the mass is broken up and transferred to a
suction funnel; soluble components are washed out with a total of
about 50 ml of hexane. Re-crystallization from about 100 ml of
dimethylformamide leaves 6.43 g of pure product as shiny flakes
(50.0%). M.p. 294-296.degree. C.
.sup.1H-n.m.r. spectum (400 MHz, (CD.sub.3).sub.2SO,
Si(CH.sub.3).sub.4=0): .delta..sub.CH3(pos.2)=2.33 ppm, s, 3H;
C.sub.7-chain:
.delta..sub.CH2(pos.3)=2.41, dist. t, 2H;
.delta..sub.(CH2)5(middle)=1.2-1.4, indistinct features, 10H;
.delta..sub.CH3=0.87, t, J=6.8 Hz, 3H.
.delta..sub.6=6.95, d-d-d, J.sub.56=12, J.sub.67.apprxeq.10,
J.sub.68.apprxeq.2.5; .delta..sub.8.apprxeq.7.0, d-d-d,
J.sub.58=1.35 (not resolved in .sup.19F-spectrum), J.sub.68=2.5,
J.sub.78=10.0, H(6)+H(8)=2H; .delta..sub.NH=11.4, s(br.),
0.85H.
.sup.19F-n.m.r. spectrum (400 MHz, (CD.sub.3).sub.2SO,
CCl.sub.3F=0): .delta..sub.5--108.6, t, J=12.7 Hz, 1F;
.delta..sub.7=-106.3, quartett, J=10.6 Hz, 1F.
Mass spectrum: M.sup.+=293, 18%; (M-C.sub.6H.sub.13).sup.+=208,
100%.
2-Methyl-3-(n-heptyl)-5.7-difluorquinolone (ELQ-121) through
hydrolysis of the
4-chloro-2-methyl-3-(n-heptyl)-5.7-difluorquinoline
When the anilinocrotonic acid from the above procedure is heated
with an excess of POCl.sub.3 for about two hours,
4-Chloro-2-methyl-3-(n-heptyl)-5.7-difluorquinoline is obtained.
This (2.25 g) heated with 15 ml of conc. HCl and 30 ml of water at
reflux temperature for three days, and the product filtered off
after cooling and washed with a small amount of ethanol, then ether
and ethanol again, 1.45 g (69%) of
2-Methyl-3-(n-heptyl)-5.7-difluorquinolone (Elq-121) is
obtained.
It is not necessary to purify the 2-substituted acetoacetates as is
illustrated in the following example. Only traces of ethyl
acetoacetate may be present, as this will give rise to the
formation of a quinolone unsubstituted in position 3:
2-Methyl-3-undecyl-5.7-difluoroquinolone (ELQ-148)
Ethyl 2-(n-undecyl)-acetoacetate was prepared from undecyl iodide
(26.6 .g) by reaction with an equivalent amount of the sodium
derivative of ethyl acetoacetate in ethanol (5 hours, reflux
temperature). After cooling the solvent is removed on a rotary
evaporator, 300 ml of hexane is added to the residue, and the
precipitate of salt is now easily filtered. The product is of
sufficient purity (g.c-m.s.) to dispense with further work-up.
Reaction of it (6.80 g) with 3.5-difluoroaniline (3.1 g) and 0.30 g
of p-toluenesulfonic acid monohydrate in 100 ml of benzene (water
separator, 3 days) produced the anilinocrotonic ester with very
little of the starting materials left. After removal of the
solvent, the crude product was added quickly to 30 ml of boiling
Dowtherm A and kept at boiling temperature for about 10 minutes.
The product crystallizes out upon cooling and is isolated by
filtration and washing with hexane (50 ml).
After re-crystallization from dimethylformaide (150 ml), 4.22 g
(50%) of a soft crystal mass is obtained.
M.p.=277-278.degree. C.
.sup.1H-n.m.r. spectum (400 MHz, (CD.sub.3).sub.2SO,
Si(CH.sub.3).sub.4=0): .delta..sub.CH3(pos.2)=2.32 ppm, s, 3H;
C.sub.11-chain:
.delta..sub.CH2(pos.3)=2.40, dist. t, 2H;
.delta..sub.(CH2)9(middle)=1.2-1.4, indistinct features, 18H;
.delta..sub.CH3=0.84, t, J=6.8 Hz, 3H.
.delta..sub.6=6.93, d-d-d, J.sub.56.apprxeq.12,
J.sub.67.apprxeq.10, J.sub.68.apprxeq.2.5;
.delta..sub.8.apprxeq.6.98, not resolved, H(6)+H(8)=2H;
.delta..sub.NH=11.4, s(br.), 0.9H.
.sup.19F-n.m.r. spectrum (400 MHz, (CD.sub.3).sub.2SO,
CCl.sub.3F=0): .delta..sub.5=-108.6, t, J=11.65 Hz, 1F;
.delta..sub.7=-106.3, quartett, J=10.25 Hz, 1F.
Mass spectrum: M.sup.+=349, 8%; (M-C.sub.6H.sub.13).sup.+=208,
100%.
Synthesis of the Mixed Carbonate Ester Derivative ELQ-125 of
ELQ-121 (see FIG. 3)
0.51 g of 5.7-F.sub.2-2-CH.sub.3-3-n-C.sub.7H.sub.15 quinolone
(ELQ-121) was stirred in 10 ml of anhydrous tetrahydrofuran with 75
mg of 60% NaH (in paraffin, slight excess) in a lightly capped vial
for about one half hour, when a pale yellow almost clear solution
resulted. To this solution was added 0.54 g of
CH.sub.3(OCH.sub.2CH.sub.2).sub.4OCOCl (slight excess) with
stirring. After 1 day 3 more drops of the acid chloride was added
and stirring continued for one more day. The solution was filtered
to remove a white precipitate, evaporated and chromatographed on a
short column (Kieselgel, 7 cm i.d..times.5 cm, CH.sub.2Cl.sub.2)
The sample dissolved in methylene chloride was washed onto the
column with 50 ml of CH2Cl2, followed by a 1:1-mixture of ethyl
acetate and hexane (isomer mixture). The elution was followed by
thin-layer chromatography. Later fractions contained a by-product.
The fraction containing our Elq-125 was brought to dryness, leaving
0.46 g of a very pale yellow oil (50% of theory).
.sup.1H-n.m.r. spectum (400 MHz, CDCl.sub.3, Si(CH.sub.3).sub.4=0):
.delta..sub.CH3(pos.2)=2.74 ppm, s, 3H; C.sub.7-chain:
.delta..sub.CH2(pos.3)=2.72, dist.t, overlap with
.delta..sub.CH3(pos.2), together 5H;
.delta..sub.CH2(middle)=1.2-1.6, indistinct features, 10H;
.delta..sub.CH3=0.88, t, J=6.88 Hz, 3H; polyether chain of
carbonate: .delta.=3.55-3.72, 2 m, 12H; .delta.=2.82, m, 2H;
.delta.=4.46, m, 2H; .delta..sub.CH3=3.36, s,
3H..delta..sub.6=6.97, d-d-d; J.sub.56=8.9, J.sub.67=9.6,
J.sub.68=2.5, 1H; .delta..sub.8=7.48, d-d-d, J.sub.58=1.3 (not res.
in .sup.19F-spectrum), J.sub.68=2.5, J.sub.78=9.6, 1H.
.sup.19F-n.m.r. spectrum (400 MHz, CDCl.sub.3,
Si(CH.sub.3).sub.4=0): .delta..sub.5=-108.6, quartett,
J.sub.average=8.9, 1F; .delta..sub.7=-114.2, d-d or t,
J.apprxeq.9.7 Hz, 1F.
Mass spectrum: M.sup.+=527, <1%;
CH.sub.3OCH.sub.2CH.sub.2.sup.+=59, 100%.
N.2-Dimethyl-3-isopentyl-5.7-difluoroquinoline (ELQ-151)
2-Methyl-3-isopentyl-5.7-difluoroquinolone (ELQ-138), 0.50 g, 5 ml
of dry p-dioxane and 150 mg of NaH (60% on in paraffin) were heated
in a 25-ml-Carius tube at 120.degree. C. for 5 hours. After cooling
the reaction mixture was poured into 100 ml of water and 3 times
extracted with 50 ml of ethyl acetate each. The combined extracts
were brought to dryness and run through a short column of Kieselgel
Merck (5 cm i.d., 4 cm height) with 1:1 ethyl acetate-hexane
(isomer mixture), the forerun being discarded. 0.21 g of white
crystalline residue remained after evaporation.
M.p.=154-155.degree. C.
.sup.1H-n.m.r. spectum (400 MHz, (CD.sub.3).sub.2SO,
Si(CH.sub.3).sub.4=0): .delta..sub.CH3(pos.2)=2.45 ppm, s, 3H;
C.sub.i-Pentyl-chain: .delta..sub.CH2(pos.3)=2.53, dist. t, 2H;
.delta..sub.CH2(middle)=1.21, symm. M., 2H;
.epsilon..sub.CH=0.1.58, septett, J=6.6 Hz, 1H,
.delta..sub.CH3=0.93, d, J=6.6, 6H. .delta..sub.6=7.07, d-d-d,
J.sub.56=12, J.sub.67=9.6, J.sub.68.apprxeq.2.4, 1H;
.delta..sub.8=7.42, d-d-d, J.sub.58=1.7 (not resolved in
.sup.19F-spectrum), J.sub.68=2.4, J.sub.78=12.1, 1H.
.delta..sub.NCH3=3.68. s, 3H.
.sup.19F-n.m.r. spectrum (400 MHz, (CD.sub.3).sub.2SO,
CCl.sub.3F=0): .delta..sub.5=-107.8, t, J=11.9 Hz;
.delta..sub.7=-105.7, d-t, J=12.0, J=9.5 Hz.
Mass spectrum: M.sup.+=279, 9%,
(M-CH.sub.2CH(CH.sub.3).sub.2+H).sup.+=223, 100%.
Synthesis Scheme for ELQ-300
##STR00014##
Condensation of 4-chloro-3-methoxy aniline and ethyl acetoacetate
followed by thermal cyclization provided 2-methyl-4-quinolone 1 via
Conrad-Limpach synthesis. Iodination of 1 with iodine in saturated
aqueous potassium iodide solution and n-butylamine provided the
3-iodo-4-quinolone 2. Copper-mediated coupling of 4-bromophenol and
4-trifluoromethoxyphenyl boronic acid with Hunig's base and
pyridine afforded the diaryl ether 4. Reaction of the lithium anion
of 4 with boron triisopropoxide followed by acidic hydrolysis of
the resulting boronic ester provided the boronic acid 5.
Suzuki-Miyaura reaction of the 3-iodo-4-quinolone 2 with the
boronic acid 5 resulted in difficult to separate mixtures of
quinolone starting material and product. This difficulty in
separation was likely the result of a combination of pi-stacking
and intermolecular hydrogen bonding typical of 4-quinolones. A
functional group protection strategy involving the 4-position
alcohol was devised that would alleviate this problem by mitigating
intermolecular hydrogen bonding. To this end 4-O-carbonates and
4-O-acetates were prepared, but these were found to be labile under
Suzuki-Miyaura reaction conditions. A more robust protecting group,
a 4-O-ethyl ether, was shown to be stable under these reaction
conditions, yet reactive enough to be selectively removed in the
presence of an aryl methoxy moiety. The 3-iodo-quinolone 2 was
reacted with ethyl iodide and potassium carbonate to give the
corresponding ethyl ether 3. Suzuki-Miyaura coupling of 3 with
4-phenoxyphenylboronic acid using palladium tetrakis
triphenylphosphine and aqueous potassium carbonate provided 3 in
very good yield. ELQ-300 was obtained in quantitative yield by
heating the ethyl ether 3 in 30% hydrobromic acid in acetic
acid.
Experimental
General. .sup.1H NMR spectra were taken on a Varian 400 MHz
instrument. Data reported were calibrated to internal TMS (0.0 ppm)
for all solvents and are reported as follows: chemical shift,
multiplicity (bs, broad singlet; s, singlet; d, doublet; t,
triplet; q, quartet; and m, multiplet), coupling constant and
integration. High-resolution mass spectrometry (HRMS) using
electrospray ionization was performed by the PSU BioAnalytical Mass
Spectrometry Facility. Inert atmosphere operations were conducted
under argon in flame-dried glassware. Anhydrous solvents and
reagents were purchased from Sigma-Aldrich or Acros and were used
without further purification. Final compounds were judged to be
>95% pure by .sup.1H NMR analysis.
##STR00015##
6-Chloro-7-methoxy-2-methylquinolin-4(1H)-one (1). A solution of
5-amino-2-chloroanisole (10.0 g, 63.5 mmol), ethyl acetoacetate
(8.1 ml, 63.5 mmol) and catalytic para-toluene sulfonic acid (302
mg, 1.59 mmol) in 65 ml benzene over 4 A molecular sieves was
stirred 6 hours at reflux (90.degree. C. external temperature). The
reaction mixture was then filtered and concentrated in vacuo. A
mixture of the resulting residue and 6.4 ml DOWTHERM A was heated
to 250.degree. C. for 20 min. The reaction mixture was cooled to
room temperature, and the precipitate was washed with hexanes and
ethyl acetate to give 6.43 g (45% yield) of
6-chloro-7-methoxy-2-methylquinolin-4(1H)-one as a light brown
solid. .sup.1H NMR (400 MHz, DMSO-d6) .delta. 11.54 (bs, 1H), 7.94
(s, 1H), 7.02 (s, 1H), 5.86 (s, 1H), 3.94 (s, 3H), 2.31 (s,
3H).
##STR00016##
6-chloro-3-iodo-7-methoxy-2-methylquinolin-4(1H)-one (2). To a
stirred solution of 6-chloro-7-methoxy-2-methylquinolin-4(1H)-one
(6.43 g, 28.7 mmol) and n-butylamine (28 ml, 287 mmol) in
dimethylformamide (57 ml) cooled by a room temperature water bath
was added iodine (7.30 g, 28.7 mmol) in a saturated solution of
aqueous potassium iodide (29 ml). The reaction mixture was stirred
12 hours at room temperature. Residual iodine was quenched with 0.1
M aqueous sodium thiosulfate, and the resulting solution was
concentrated in vacuo. The residue was resuspended in water and
filtered to give 8.93 g (89% yield) of
6-chloro-3-iodo-7-methoxy-2-methylquinolin-4(1H)-one as a light
brown powder.
.sup.1H NMR (400 MHz, DMSO-d6) .delta. 11.65 (bs, 1H), 7.59 (s,
1H), 6.41 (s, 1H), 3.91 (s, 3H), 2.18 (s, 3H).
##STR00017##
6-chloro-4-ethoxy-3-iodo-7-methoxy-2-methylquinoline (3). To a
stirred solution of
6-chloro-3-iodo-7-methoxy-2-methylquinolin-4(1H)-one (2.00 g, 5.72
mmol) in dimethylformamide (57 ml) was added potassium carbonate
(1.58 g, 11.4 mmol) at room temperature. The resulting suspension
was stirred 0.5 hours at 50.degree. C. Ethyl iodide was added
dropwise at room temperature, and the reaction mixture was stirred
8 hours at 50.degree. C. The solvent was removed in vacuo and the
resulting residue was resuspended in ethyl acetate and water. The
organic layer was extracted with brine, dried over magnesium
sulfate and concentrated in vacuo to give 2.12 g (99% yield) of
6-chloro-4-ethoxy-3-iodo-7-methoxy-2-methylquinoline as a light
brown solid. .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 7.99 (s,
1H), 7.40 (s, 1H), 4.19 (q, J=7.1 Hz, 2H), 4.02 (s, 3H), 2.92 (s,
3H), 1.61 (t, J=7.1 Hz, 3H).
##STR00018##
1-Bromo-4-(4-(trifluoromethoxy)phenoxy)benzene (4). To a solution
of 4-(trifluoromethoxy)phenylboronic acid (10.0 g, 48.6 mmol) and
4-bromophenol (4.20 g, 24.3 mmol) in dichloromethane (250 ml) over
4 A molecular sieves was added copper (II) acetate (4.41 g, 24.3
mmol), diisopropylethylamine (21 ml, 121 mmol) and pyridine (10 ml,
121 mmol). The reaction mixture was stirred 12 hours at room
temperature under positive pressure of dry air and concentrated in
vacuo. The resulting residue was resuspended in ethyl acetate and
0.5 M HCl. The organic layer was extracted with water and brine,
dried over magnesium sulfate and concentrated in vacuo.
Purification by silica gel chromatography (ethyl acetate/hexanes)
provided 5.07 g 1-bromo-4-(4-(trifluoromethoxy)phenoxy)benzene (63%
yield) as a clear oil. .sup.1H NMR (400 MHz, CDCl.sub.3) .delta.
7.45 (d, J=9.3 Hz, 1H), 7.19 (d, J=8.9 Hz, 1H), 6.99 (d, J=9.3 Hz,
1H), 6.89 (d, J=8.9 Hz, 1H).
##STR00019##
(4-(4-(Trifluoromethoxy)phenoxy)phenyl)boronic acid (5). To a
solution of 1-bromo-4-(4-(trifluoromethoxy)phenoxy)benzene (5.07 g,
15.2 mmol) in THF (76 ml) at -78.degree. C. was added n-butyl
lithium (7.6 ml, 2.5 M in hexanes, 19.0 mmol) dropwise. The
reaction mixture was stirred 0.5 hours at -78.degree. C., and
triisopropylborate (7.0 ml, 30.4 mmol) was added. The reaction was
stirred 4 hours at room temperature, quenched with 1 N HCl and
stirred 0.5 hours at 0.degree. C. The aqueous layer was extracted
with ethyl acetate. The combined organic layers were extracted with
brine and dried over magnesium sulfate. Purification by silica gel
chromatography (0-10% methanol in dichloromethane) provided 4.38 g
(4-(4-(trifluoromethoxy)phenoxy)phenyl)boronic acid (97% yield) as
a light brown viscous oil. .sup.1H NMR (400 MHz, CDCl.sub.3)
.delta. 8.20 (d, J=8.9 Hz, 1H), 7.26 (d, J=8.9 Hz, 1H), 7.07-7.14
(m, 2H).
##STR00020##
6-chloro-4-ethoxy-7-methoxy-2-methyl-3-(4-(4-(trifluoromethoxy)phenoxy)
phenyl) quinoline (6). To a solution of
6-chloro-4-ethoxy-3-iodo-7-methoxy-2-methylquinoline (1.56 g, 4.13
mmol), (4-(4-(trifluoromethoxy)phenoxy)phenyl)boronic acid (1.85 g,
6.20 mmol) and palladium (0) tetrakis triphenylphosphine (239 mg,
0.207 mmol) in degassed dimethylformamide was added 8.25 ml of a 2
N aqueous potassium carbonate solution. The reaction mixture was
stirred 18 hours at 85.degree. C., filtered through celite and
concentrated in vacuo. The resulting residue was resuspended in
dichloromethane and water. The organic layer was extracted with
brine, dried over magnesium sulfate and concentrated in vacuo.
Purification by silica gel chromatography (0-20% ethyl acetate in
dichloromethane) provided 1.18 g
6-chloro-4-ethoxy-7-methoxy-2-methyl-3-(4-(4-(trifluoromethoxy)phenoxy)ph-
enyl)quinoline (57% yield) as a light brown solid. .sup.1H NMR (400
MHz, CDCl.sub.3) .delta. 8.11 (s, 1H), 7.43 (s, 1H), 7.31-7.36 (m,
2H), 7.22-7.26 (m, 2H), 7.07-7.14 (m, 4H), 4.04 (s, 3H), 3.71 (q,
J=7.1 Hz, 2H), 2.49 (s, 3H), 1.18 (t, J=7.1 Hz, 3H).
##STR00021##
6-chloro-7-methoxy-2-methyl-3-(4-(4-(trifluoromethoxy)phenoxy)phenyl)quin-
olin-4(1H)-one (ELQ-300). To a solution of
6-chloro-4-ethoxy-7-methoxy-2-methyl-3-(4-(4-(trifluoromethoxy)phenoxy)ph-
enyl)quinoline (1.16 g, 2.30 mmol) in acetic acid (10 ml) was added
a 50% aqueous hydrobromic acid solution (5 ml). The reaction
mixture was stirred 24 hours at 90.degree. C., cooled and
concentrated in vacuo. The resulting residue was resuspended in
water, neutralized with 2 N NaOH and filtered. The collected solid
was triturated with dichloromethane and filtered to provide 923 mg
6-chloro-7-methoxy-2-methyl-3-(4-(4-(trifluoromethoxy)phenoxy)phenyl)quin-
olin-4(1H)-one (84% yield) as a white powder. .sup.1H NMR (400 MHz,
CDCl.sub.3) .delta. 11.97 (s, 1H), 8.05 (s, 1H), 7.42 (d, J=8.7 Hz,
2H), 7.29 (d, J=8.3 Hz, 2H), 7.17 (d, J=8.3 Hz, 2H), 7.12 (s, 1H),
7.08 (d, J=8.7 Hz, 2H), 3.97 (s, 3H), 2.26 (s, 3H). HRMS (EI+) m/z
for C.sub.24H.sub.17ClF.sub.3NO.sub.4: calculated 475.0798, found
475.0801.
Preparation of
6-chloro-3-(2-fluoro-4-(4-(trifluoromethoxy)phenoxy)phenyl)-7-methoxy-2-m-
ethylquinolin-4(1H)-one [RMMC 391]
##STR00022##
An oven-dried Schlenk tube was flame-dried and backfilled with
argon (3.times.). The tube was then charged with
6-chloro-4-ethoxy-3-(2-fluoro-4-(4-(trifluoromethoxy)phenoxy)phenyl)-7-me-
thoxy-2-methylquinoline (0.3 g, 0.8 mmol), Pd(PPh.sub.3).sub.4
(0.08 g, 10 mol %), and
2-fluoro-4-(4-(trifluoromethoxy)phenoxy)phenylboronic acid (0.375
g, 1.2 mmol). A rubber septum was then placed on the tube and 2M
Na.sub.2CO.sub.3 (3 mL), DMF (15 mL), were added. The tube was then
purged of air by argon for about 1 minute, while stirring and then
heated at 90.degree. C. until completion by HPLC analysis .about.3
h. After completion, reaction was boiled with 1:1 MeOH/CHCl.sub.3,
and filtered over celite. The celite was then rinsed with boiling
hot DMF. The filtrate was then evaporated on silica gel purified
via flash chromatography (33% EtOAc in Hexane). The resulting
amorphous solid (0.48 g, 52%) was then dissolved in 4.8 mL of AcOH
and 4.8 mL of HBr. This solution was refluxed for 1.5 h. The
reaction was poured onto ice and water. The resulting solid was
filtered via filtration and recrystallized from DMF twice (0.2 g,
44%).
.sup.1H NMR (400 MHz, DMSO) .delta. 11.79 (s, 1H), 7.99 (d, J=1.3
Hz, 1H), 7.44 (d, J=8.9 Hz, 2H), 7.29 (t, J=8.0 Hz, 1H), 7.23 (dd,
J=9.0, 1.2 Hz, 2H), 7.08 (s, 1H), 6.99 (d, J=10.4 Hz, 1H), 6.90 (d,
J=10.1 Hz, 1H), 3.97 (s, 3H), 2.20 (s, 3H). .sup.13C NMR (101 MHz,
CDCl.sub.3) .delta. 173.09, 160.46 (d, J=246.6 Hz), 156.79, 156.66
(d, J=246.6 Hz), 154.87, 147.54, 144.07, 139.67, 134.22 (d, J=5.05
Hz), 126.03, 123.04, 120.43, 118.68 (d, J=17.17 Hz), 118.27 (d,
J=16.16 Hz), 114.05, 113.93 (d, J=103 Hz), 106.13 (d, J=26.26 Hz),
99.51, 56.32, 18.24. .sup.19F NMR (376 MHz, CDCl.sub.3) .delta.
-52.56, -105.28.
Preparation of
2-fluoro-4-(4-(trifluoromethoxy)phenoxy)phenylboronic acid
##STR00023##
4-(4-(trifluoromethoxy)phenoxy)phenylboronic acid (120). In a
flame-dried 25 mL schlenk tube backfilled with argon (.times.3) a
solution of 4-bromo-3-fluorophenol (0.346 g, 2 mmol) in
N-methylpyrrolidine (8 mL) under an argon atmosphere was added
4-(trifluoromethoxy)iodobenzene (0.626 mL, 4 mmol),
2,2,6,6-tetramethylheptane-3,5-dione (0.092 mL, 0.44 mmol) and
cesium carbonate (1.30 g, 4 mmol). The slurry was degassed by
bubbling argon for 15 min and CuCl (0.099 g, 1 mmol) was then
added. The reaction mixture was again degassed and then warmed to
100.degree. C. for 7 h. After cooling to room temperature,
Et.sub.2O (75 mL) was added slowly. The resulting slurry was
filtered and the solid washed with Et.sub.2O (3.times.50 mL). The
combined filtrates were washed with 2 M NaOH (100 mL), water (100
mL), 1 M aq HCl (100 mL), water (100 mL) and saturated brine (100
mL), the subsequently dried over Na2SO4 and concentrated under
reduced pressure. The residue was purified via flash chromatography
with 100% Hexane. This column was repeated three times combining
the purest fractions each column to obtain pure material due to
similarly eluting 4-(trifluoromethoxy)iodobenzene to afford
1-bromo-2-fluoro-4-(4-(trifluoromethoxy)phenoxy)benzene (0.15 g,
45%) as a colorless liquid. To a solution of
1-bromo-2-fluoro-4-(4-(trifluoromethoxy)phenoxy)benzene (2.1 mmol,
0.7 g) and triisopropyl borate (2.7 mmol, 0.63 mL) in dry THF (15
mL) at -78.degree. C. was added dropwise 2.5M BuLi (6.5 mL) in
Hexanes over 5 minutes. The reaction was stirred for 3 h at
-78.degree. C. at which point 10 mL of 6M HCl is added and the
solution is allowed to warm up to room temperature and stir
overnight. The reaction mixture was diluted with EtOAc (150 mL) and
water (150 mL). The organic layer is taken separately and rinsed
with water (150 mL), followed by brine (150 mL) and then dried over
Na.sub.2SO.sub.4. The EtOAc is then concentrated in vacuo to afford
a waxy solid which is then treated with 2M NaOH (40 mL) and stirred
for 15 min diluted with water (300 mL) and stirred for 20 minutes.
The solution is then filtered and the filtrate washed with hexane
(3.times.100 mL). The aqueous layer was carefully acidified to pH 1
with 6 m HCl. The resulting white solid was filtered and dried on a
high vacuum overnight to afford the titled compound in 67%
yield.
.sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 7.78 (t, J=8.1 Hz, 1H),
7.22 (d, J=9.0 Hz, 2H), 7.09-7.02 (m, 2H), 6.80 (dd, J=8.3, 2.2 Hz,
1H), 6.63 (dd, J=12.0, 2.2 Hz, 1H), 5.14 (d, J=6.3 Hz, 2H).
Parasites
Plasmodium falciparum strains D6 and Dd2 were obtained from the MR4
(ATCC, Manassas, Va., USA). D6 is sensitive to chloroquine but
mildly resistant to mefloquine while Dd2 is resistant to multiple
quinoline and antifolate antimalarial agents. Tm90.C2B is resistant
to atovaquone, chloroquine, mefloquine, and quinine.
Parasite Culture and Drug Sensitivity
Three different laboratory strains of P. falciparum were cultured
in human erythrocytes by standard methods under a low oxygen
atmosphere (5% O.sub.2, 5% CO.sub.2, 90% N.sub.2) in an
environmental chamber as described in Trager, W., and J. B. Jensen.
1976. Human malaria parasites in continuous culture. Science
193:673-5. The culture medium was RPMI-1640, supplemented with 25
mM HEPES buffer, 25 mg/L gentamicin sulfate, 45 mg/L hypoxanthine,
10 mM glucose, 2 mM glutamine, and 0.5% Albumax II (complete
medium). The parasites were maintained in fresh human erythrocytes
suspended at a 2% hematocrit in complete medium at 37.degree. C.
Stock cultures were sub-passaged every 3 to 4 days by transfer of
infected red cells to a flask containing complete medium and
uninfected erythrocytes.
In vitro antimalarial activity of the compounds was assessed by the
SYBR Green I fluorescence-based method (the "MSF assay") described
previously by Smilkstein, M., N. Sriwilaijaroen, J. X. Kelly, P.
Wilairat, and M. Riscoe. 2004. Simple and inexpensive
fluorescence-based technique for high-throughput antimalarial drug
screening. Antimicrob Agents Chemother 48:1803-6 with minor
modifications (Winter, R. W., J. X. Kelly, M. J. Smilkstein, R.
Dodean, G. C. Bagby, R. K. Rathbun, J. I. Levin, D. Hinrichs, and
M. K. Riscoe. 2006. Evaluation and lead optimization of
anti-malarial acridones. Exp Parasitol 114:47-56). Experiments were
set up in triplicate in 96 well plates (Costar, Corning) with
two-fold dilutions of each drug across the plate in a total volume
of 100 microliters and at a final red blood cell concentration of
2% (v/v). Stock solutions of each drug were prepared by dissolving
in ethanol or dimethylsulfoxide (as appropriate) at 10 mM. Each
dilution series was initiated at a concentration of 1 .mu.M and the
experiment was repeated beginning with a lower initial
concentration for those compounds in which the IC.sub.50 value was
below 10 nM. Automated pipeting and dilution was carried out with
the aid of a programmable Precision 2000 robotic station (BioTek,
Winooski, Vt.). An initial parasitemia of 0.2% was attained by
addition of normal uninfected red cells to a stock culture of
asynchronous parasite infected red cells (PRBC). The plates were
incubated for 72 hrs at 37.degree. C. in an atmosphere of 5%
CO.sub.2, 5% O.sub.2, and 90% N.sub.2. After this period the SYBR
Green I dye-detergent mixture (100 .mu.l) was added and the plates
were incubated at room temperature for an hour in the dark and then
placed in a 96-well fluorescence plate reader (Spectramax
Gemini-EM, Molecular Diagnostics) for analysis with excitation and
emission wavelength bands centered at 497 and 520 nm, respectively.
The fluorescence readings were plotted against the logarithm of the
drug concentration and curve fitting by nonlinear regression
analysis (GraphPad Prism software) yielded the drug concentration
that produced 50% of the observed decline relative to the maximum
readings in drug-free control wells (IC.sub.50).
In vivo Efficacy in a Murine Malaria Model of Patent Infection with
P. yoelii
The activity of the ester, ELQ-125, against the blood stages was
assessed using a modified Thompson procedure (Arba Ager, 1984).
Rodent malaria models, vol. 68/1. Springer-Verlag, Berlin. Mice
(female, CF1) were infected intravenously with 1-5 million P.
yoelii parasitized erythrocytes from a donor animal. Drug
administration was initiated once the parasitemia had risen to
between 3 to 5% as determined microscopically by examination of
Giemsa-stained blood smears. The test compound, ELQ-125, was taken
into NeoBee M-5 (Stephan Company, Northfield, Ill., USA) and used
without dilution. The drug was administered by gavage once daily
for 3 days. On the 4.sup.th day blood films were prepared and the
extent of parasitemia was determined microscopically. ED.sub.50 and
ED.sub.90 values (mg/kg/day) were derived from the dose required to
reduce the parasite burden by 50% and 90%, respectively, relative
to drug-free controls. The procedures involved, together with all
matters relating to the care and housing of the animals used in
this study, were approved by the Portland VA Medical Center
Institutional Animal Care and Use Committee (approval #0807).
Prodrugs containing a water-soluble pro-moiety that could be
metabolically released after drug administration were designed and
synthesized. A prodrug ester of ELQ-121 was synthesized and it was
found that the prodrug formulation (ELQ-125) exhibits improved
water solubility, miscibility with NeoBee M-5, a pharmaceutical
delivery vehicle, and greatly enhanced in vivo efficacy. In a test
of drug efficacy against a patent P. yoelii infection in mice with
a parasitemia (5 mice/group) at the beginning of a 3-day (once
daily) treatment regimen, doses of 100 mg/kg/day and 50 mg/kg/day
completely cleared parasites from the bloodstream without evident
toxicity based on weight loss, grooming and locomotion. In each
case, ELQ-125, a clear and colorless syrup, was administered orally
with NeoBee M-5 (vol.=100 .mu.l). At 25 mg/kg/day, parasitemia was
suppressed by >99% relative to controls (assessed on the day
following the last dose) and the animals in this group remained
parasite-free until they were euthanized 10 days later. A follow-up
study in which the drug was administered in 100 .mu.l NeoBee M5
established ED.sub.90 (22 mg/kg/day) and ED.sub.50 (11 mg/kg/day)
values for ELQ-125 in the same mouse system.
Although not bound by any theory, it is believed that these results
have great significance. The poly-ethylene glycol (PEG) promoiety,
a "first-of-a-kind" construct, proved to be highly efficacious by
oral dosing. Taken together with other enhancements incorporated
into the pharmacophore, at least two major obstacles (enhanced
solubility and metabolic stability) have been overcome that have
blocked the therapeutic advancement of endochin for over 60 years.
In addition, by introducing chemical features into the
4(1H)-quinolone core that enhance aqueous solubility without
compromising antiparasitic activity or metabolic stability,
quinolones can be designed that are efficacious and curative
without the promoiety.
In vitro Activity and Pharmaco-Resistance Pattern of Quinolones
Against a Panel of P. falciparum parasites
The compounds were screened for antiplasmodial activity in vitro
against chloroquine (CQ) sensitive (D6), multidrug resistant (Dd2),
and chloroquine/quinine/atovaquone (ATV)-resistant (Tm90.C2B)
strains of P. falciparum. The compound structures and results are
provided in Table 1 (FIG. 4). It may be observed that endochin
(ELQ-100) exhibits potent activity with IC.sub.50 values of
.apprxeq.3-4 nM vs. D6 and Dd2, and 11.4 nM vs. the ATV-resistant
Tm90.C2B clinical isolate, i.e., a modest level of ATV
cross-resistance. Exploration of the structure-activity
relationships revealed that the potency of the endochin molecule
can be greatly influenced by chemical modification. The following
observations on the structure-activity relationships (SAR) can be
made: 1. It may be observed that the length of the 3-position side
chain influences the antiplasmodial effect. Our data show that the
7 carbon chain length (endochin) is superior to C6>C5>C4 with
values ranging from .apprxeq.3 nM (ELQ-100) to .apprxeq.30 nM (C4,
ELQ-115). ELQ-103 with a trifluoroundecyl side chain exhibits
IC.sub.50 values in the low nanomolar range for all 3 tested
strains. 2. Replacement of the 7-OCH.sub.3 group by hydroxy
(ELQ-117) greatly diminishes antiplasmodial activity whereas
replacement by either Cl (ELQ-109) or F (ELQ-120) results in only a
modest reduction in in vitro potency. Derivatives bearing other
electronegative substituents at the 7-position (e.g., CN, CF.sub.3,
OCF.sub.3, and NO.sub.2) proved inferior, and all of these
molecules exhibited modest to significant cross-resistance against
the Tm90.C2B strain, It is interesting that the in vitro activity
of the 7-H analog (ELQ-127) is weakened by roughly 5-fold relative
to that of endochin however it remains equally active against all
three parasite strains. 3. In certain embodiment, the 2-CH.sub.3
group may be important because replacement of it with a hydroxy is
accompanied by a dramatic loss of effectiveness, e.g., compare
ELQ-100 to ELQ-106 vs. the D6 strain with IC.sub.50 values of 3.8
nM and >2,500 nM, respectively. 4. Moving the chlorine atom from
the 7 position (e.g., ELQ-109) to the 6-position (e.g., ELQ-130)
results in a modest reduction in antimalarial response (strain D6
IC.sub.50 values of 5.8 nM and 22.2 nM, respectively) however equal
sensitivity is observed against the atovaquone-resistant Tm90.C2B
clinical isolate only for ELQ-130. Similar results were observed
for the congener with a fluorine atom at position 6 (ELQ-131).
Taken together with results from the 7-H derivative, ELQ-127, these
observations combine to suggest that the mutation appearing in the
cytochrome b gene of this clinical isolate (which is linked to a
high level of atovaquone resistance) introduces steric hindrance to
bulky substituents occupying the 7-position of quinolone ring
system. 5. Placement of 2 halogens on the benzenoid ring had a
mixed effect. The 5,7-dichloro endochin analog (ELQ-124) exhibited
weak in vitro activity while the corresponding 5,7-difluoro
construct (ELQ-121) proved to be one of the most potent compounds
in the tested series with IC.sub.50 values of .apprxeq.0.05 nM
against D6 and Dd2 and about 300 times higher against Tm90.C2B. By
contrast, the 6,8-difluoro positional isomer was vastly inferior
with IC.sub.50 values ranging from .apprxeq.110 nM to 134 nM for
all 3 strains, i.e., potency was diminished by .apprxeq.2,000-fold.
6. Particularly revealing are the results of testing ELQ-134 and
ELQ-119, structural analogs of the most potent quinolone construct.
ELQ-134 is the N-methyl derivative of ELQ-121 and it shows greatly
diminished potency (roughly 300-fold reduced); its metabolic
stability will be evaluated. ELQ-119 contains a chlorine atom at
the 4-position and it is over a 1,000 times less potent than the
parent drug based on in vitro testing.
Determination of anti-T. gondii IC.sub.50 and TD.sub.50 values--use
of the 2F strain. This method, which employs tachyzoites of
Toxoplasma gondii strain 2F that constitutively expresses
cytoplasmic Beta-galactosidase, has been described recently by
Jones-Brando et al. (Jones-Brando, L., D'angelo, J., Posner, G H,
and Yolken, R., 2006, In vitro inhibition of Toxoplasma gondii by
four new derivatives of artemisinin, Antimicrobial Agents and
Chemotherapy 50: 4206-8). The compounds disclosed herein were
examined at concentrations ranging from 0 to 320 .mu.M; the initial
test range is from 10 nM to 320 .mu.M and if necessary a follow-up
test was conducted in a lower concentration range sufficient to
bracket the IC.sub.50. Briefly, each drug was dissolved in ethanol
or DMSO, as appropriate, at a concentration of 10 mM and diluted
with complete Dulbecco's modified Eagle's medium (DMEM) to 1,000
.mu.M. Test and control drugs were added to human foreskin
fibroblasts (HFF) cells that were grown overnight in 96-well plates
in DMEM containing 10% fetal calf serum. On the following day the
culture medium was replaced with DMEM containing 1% fetal calf
serum. After drug addition, 50 T. gondii tachyzoites were then
added to each well and the plates were incubated at 37.degree. C.
in a humidified atmosphere with supplemental 5% CO.sub.2. After 96
hrs the substrate for beta-galactosidase,
chlorophenolred-beta-D-galactopyranoside (CPRG), was added and the
plates were incubated for another 24 hr. After this period, Triton
X-100 is added to inactivate the parasite and the color reactions
in the wells were read in a microplate reader. The data were
analyzed as detailed below. For anti-T. gondii IC.sub.50
determinations, the plates are read at 570-650 nm. The amount of
absorbance (570-650 nm) in wells containing drug, parasites, and
CPRG reagent is compared to that in control wells containing T.
gondii, HFF cells and CPRG. The amount of absorbance in these wells
is directly proportional to the amount of beta-galactosidase
activity and thus correlative to the number of viable tachyzoites
in each well. Thus, a decrease in the amount of absorbance
indicates an inhibition of parasite growth. Percent inhibition is
calculated for each drug concentration and then the median
inhibitory concentration reducing parasite growth by 50% relative
to no-drug controls (IC.sub.50) is calculated by extrapolation of
the dose-response curve on a log-linear plot employing the portions
of the curve that transect the 50% response point. Cytotoxicity
induced by each ELQ against HFF cells is determined by use of the
CellTiter 96 Aqueous One Reagent (Promega) yielding TD.sub.50
(median cytotoxic dose) values calculated in the same manner as the
IC.sub.50. The primary goal of the drug testing studies is the
determination of the median inhibitory (IC.sub.50) and cytotoxic
(TD.sub.50) concentrations. The ratio of the TD.sub.50/IC.sub.50 is
used to generate the in vitro therapeutic index (IVTI), a measure
of selectivity, for each compound.
The compounds and results are shown in Table 2 (FIG. 5). In summary
of our findings of the structure-activity profiles of endochin-like
quinolones (ELQs) as antitoxoplasmic agents, we observe essentially
the same correlation as observed for Plasmodium falciparum except
that the N-alkyl derivatives (e.g., ELQ-134) exhibit enhanced
growth inhibitory activity against Toxoplasma gondii.
Several embodiments of the compounds, composition and method
disclosed herein are described below with reference to the
following numbered paragraphs:
1. A compound of formula I:
##STR00024##
or formula II:
##STR00025##
or a pharmaceutically acceptable salt of formula I or formula II,
wherein:
R.sup.1 is H, hydroxyl, alkoxy, acyl, alkyl, cycloalkyl, aryl, or
heteroaryl;
R.sup.2 is methyl, haloalkyl, or heteroaryl;
R.sup.4 is hydroxyl, carbonyloxy, or carbonyldioxy;
R.sup.3 is aliphatic, aryl, aralkyl, or alkylaryl; and
R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each individually H,
halogen, alkoxy, alkyl, haloalkyl, aryl, nitro, cyano, amino,
amido, acyl, carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10,
wherein R.sup.10 is H, alkyl, amino or haloalkyl;
provided that in formula I, R.sup.5 and R.sup.7 are not both H or
R.sup.6 is not H or methoxy; and in formula II that if R.sup.4 is
carbonyldioxy then R.sup.7 is not methoxy.
2. The compound of paragraph 1, wherein R.sup.5 and R.sup.7 of
formula I or II are each halogen or haloalkyl.
3. The compound of paragraph 1, wherein R.sup.5 and R.sup.7 of
formula I or II are each F.
4. The compound of any one of paragraphs 1 to 3, wherein R.sup.4 is
carbonyloxy or carbonyldioxy.
5. The compound of any one of paragraphs 1 to 4, wherein R.sup.7 of
formula I or II is not methoxy.
6. The compound of any one of paragraphs 1 to 5, wherein R.sup.6 of
formula I or II is halogen and R.sup.5 and R.sup.7 are each H.
7. The compound of any one of paragraphs 1 to 6, wherein R.sup.2 of
formula I or II is methyl.
8. The compound of any one of paragraphs 1 to 7, wherein R.sup.3 of
formula I or II is a branched alkyl, linear alkyl, cycloalkyl,
alkoxy, branched alkenyl, linear alkenyl or cycloalkenyl.
9. The compound of paragraph 8, wherein the branched or linear
alkyl or branched or linear alkenyl is substituted at its terminal
end with one or more fluorine atoms.
10. The compound of any one of paragraphs 1 to 9, wherein R.sup.1
is H, alkyl, or cycloalkyl.
11. The compound of any one of paragraphs 1 to 9, wherein R.sup.1
is alkyl.
12. The compound of paragraph 1, wherein in formula 1:
R.sup.1 is H or alkyl;
R.sup.2 is methyl;
R.sup.5 and R.sup.7 are each F; and
R.sup.6 and R.sup.8 are each H.
13. The compound of paragraph 1, wherein in formula I:
R.sup.1 is H or alkyl;
R.sup.2 is methyl;
R.sup.5, R.sup.7 and R.sup.8 are each H; and
R.sup.6 is halogen.
14. The compound of any one of paragraphs 1 to 13, wherein R.sup.8
of formula I or II is H.
15. The compound of any one of paragraphs 1 to 11 or 14, wherein
the compound of formula II has a structure represented by formula
III:
##STR00026##
wherein R.sup.9 is alkyl, alkenyl, alkyl amino, amido,
aminocarbonyl, hydroxyalkyl, alkoxyalkyl or alkyl ether.
16. The compound of any one of paragraphs 1 to 11 or 14, wherein
the compound of formula II has a structure represented by formula
IV:
##STR00027##
wherein R.sup.9 is alkyl, alkenyl, alkyl amino, amido,
aminocarbonyl, hydroxyalkyl, alkoxyalkyl or alkyl ether.
17. The compound of any of paragraphs 1 to 7 or 10 to 16, wherein
R.sup.3 is cycloalkyl, hetero-cycloalkyl, aliphatic ether,
trifluoromethoxy-aliphatic ether, arahaloalkyl,
trifluoromethoxy-diarylether, alkyl-heteroaryl, or
alkyl-halogenated heteroaryl.
18. The compound of any one of paragraphs 1 to 7 or 10 to 16,
wherein R.sup.3 is a cycloalkyl, heterocycloalkyl, or
heteroaryl.
19. The compound of paragraph 18, wherein R.sup.3 is
##STR00028##
wherein R.sup.11 is C or a heteroatom that may be at any position
on the ring; a is 3 to 6; R.sup.12 is selected from at least one of
alkoxy, halogen-substituted alkoxy, halogenated lower alkyl, alkyl,
methylsulfonyl, or halogen; and b is 0 to 5.
20. The compound of any one of paragraphs 1 to 7 or 10 to 16,
wherein R.sup.3 is an alkynyl.
21. The compound of paragraph 20, wherein R.sup.3 is
##STR00029##
wherein R.sup.11 is C or a heteroatom that may be at any position
on the ring; a is 3 to 6; R.sup.12 is selected from at least one of
alkoxy, halogen-substituted alkoxy, halogenated lower alkyl, alkyl,
methylsulfonyl, or halogen; and b is 0 to 5.
22. The compound of any one of paragraphs 1 to 7 or 10 to 16,
wherein R.sup.3 is a diaryl ether.
23. The compound of paragraph 22, wherein R.sup.3 is
##STR00030##
wherein R.sup.13 and R.sup.14 are each individually selected from
at least one of alkoxy, halogen-substituted alkoxy, halogenated
lower alkyl, alkyl, methylsulfonyl, or halogen; c is 0 to 5; and d
is 0 to 5.
24. The compound of paragraph 1, wherein R.sup.1 is H; R.sup.2 is H
or methyl; R.sup.3 is cycloalkyl, heterocycloalkyl, heteroaryl,
alkynyl or diaryl ether; R.sup.6 is halogen; R.sup.7 is H or
methoxy; and R.sup.5 and R.sup.8 are each H.
25. A compound of formula XI:
##STR00031##
or a pharmaceutically acceptable salt of formula XI, wherein:
R.sup.1 is H, hydroxyl, alkoxy, acyl, alkyl, cycloalkyl, aryl, or
heteroaryl;
R.sup.2 is H, carboxyl, substituted carboxyl, alkyl, haloalkyl, or
heteroaryl;
R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each individually H,
halogen, alkoxy, alkyl, haloalkyl, aryl, nitro, cyano, amino,
amido, acyl, carboxyl, substituted carboxyl, or --SO.sub.2R.sup.10,
wherein R.sup.10 is H, alkyl, amino or haloalkyl; and
R.sup.3 is an optionally substituted cycloalkyl, an optionally
substituted heterocycloalkyl, an optionally substituted heteroaryl,
an optionally substituted alkynyl or an optionally substituted
diaryl ether.
26. The compound of paragraph 25, wherein R.sup.1 is H; R.sup.2 is
H or methyl; R.sup.6 is halogen; R.sup.7 is H or methoxy; and
R.sup.5 and R.sup.8 are each H.
27. A composition comprising a pharmacologically active amount of
at least one compound of any one of paragraphs 1 to 26 or a
pharmaceutically acceptable salt thereof, and at least one
pharmaceutically acceptable carrier.
28. A method for inhibiting a parasitic or infectious disease in a
subject comprising administering to the subject a therapeutically
effective amount of a compound of any one of paragraphs 1 to 26 or
a pharmaceutically acceptable salt thereof.
29. The method of paragraph 28, wherein the parasitic disease is
malaria.
30. The method of paragraph 29, wherein the malaria is
multidrug-resistant malaria.
31. The method of paragraph 29, wherein the malaria is
chloroquine-resistant malaria.
32. The method of paragraph 29, wherein the compound exhibits
equipotency against chloroquine-resistant and multidrug-resistant
strains of Plasmodium parasites.
33. The method of any one of paragraphs 28 to 32, wherein the
compound of any one of paragraphs 1 to 26 is co-administered with
at least one other antimalarial agent.
34. A method for inhibiting a parasitic disease in a subject
comprising administering to the subject a therapeutically effective
amount of a composition of paragraph 27.
35. The method of any one of paragraphs 28 to 34, wherein the
method comprises prophylactic treating the subject against
chloroquine-resistant or multidrug-resistant malaria.
36. The method of paragraph 28, wherein the parasitic disease is
toxoplasmosis.
In view of the many possible embodiments to which the principles of
the disclosed compounds and methods may be applied, it should be
recognized that the illustrated embodiments are only preferred
examples and should not be taken as limiting the scope of the
invention.
* * * * *